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The effect of methylphenidate and mixed amphetamine salts on cognitive reflection: a field study. Psychopharmacology (Berl) 2022; 239:455-463. [PMID: 34729642 DOI: 10.1007/s00213-021-06016-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/20/2021] [Indexed: 10/19/2022]
Abstract
RATIONALE Methylphenidate (MPH) and mixed D,L-amphetamine salts (MASs; Adderall) were previously found to have unreliable effects on judgment and decision processes. OBJECTIVE We predicted that MPH and MASs have a specific effect of reducing heuristic responses, which should lead to increased performance on the cognitive reflection test (CRT). The CRT is considered to be a testbed for heuristic versus deliberative response modes. METHODS We recruited a sample of 15,361 individuals using the Prolific Academic crowdsourcing platform. From this initial pool, our final sample consisted of 294 participants (125 MPH users and 169 MASs users) who conformed to the study criteria and completed the experimental tasks. Tasks were performed on days where participants were either medicated or not, allowing to assess the effect of medication status. RESULTS There was a strong positive effect of taking MPH on CRT scores (Cohen's d = 0.40) which was not qualified by frequency of MPH usage, ADHD symptoms, and demographic factors. There was also a somewhat weaker effect for MASs (Cohen's d = 0.07). No effects of MPH and MASs were recorded for risk-taking and numeracy. CONCLUSIONS The results indicate that MPH enhances decision-making in tasks where heuristic responses typically bias it.
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Çelik HEA, Ceylan D, Ongun CH, Erdoğan A, Tan D, Gümüşkesen P, Bağci B, Özerdem A. Neurocognitive Functions in Bipolar Disorder in Relation to Comorbid ADHD. ACTA ACUST UNITED AC 2021; 58:87-93. [PMID: 34188588 DOI: 10.29399/npa.27290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/20/2020] [Indexed: 11/07/2022]
Abstract
Introduction Bipolar disorder (BD) and attention deficit hyperactivity disorder (ADHD) often co-occur in adult population. Both conditions present various neurocognitive and behavioral problems. We aimed to examine neurocognitive functions in adult patients with comorbid BD and ADHD (BD+ADHD) in comparison to patients with only BD, only ADHD and healthy controls (HCs). Method An extensive cognitive battery which evaluates verbal learning and memory, visual memory, processing speed, attention, executive functions, working memory and verbal fluency, was used to assess neurocognitive functions respectively in adult (age 18-65 years) patients with BD (n=37), ADHD (n=43), BD+ADHD (n=20) in comparison to HCs (n=51). The Multivariate Analysis of Covariance models, where age, level of education and total BIS-11 scores were included as covariates, were used for comparing neurocognitive scores among groups. Results Both BD and BD+ADHD groups showed significantly poorer performance than HCs in processing speed, attention, executive functions, and verbal fluency domains. The BD group had additional significant deficits in executive functions, verbal learning and memory domains. There were no significant differences between BD and BD+ADHD groups with regards to verbal learning and memory, visual memory, processing speed, attention, executive functions, working memory and verbal fluency domains. Patients with only ADHD showed significantly poorer performance than HCs in verbal fluency domain. Conclusions Our results show similarities in the neurocognitive functions of adults with BD and BD+ADHD across a wide range of cognitive domains. The findings point to the need for further exploration of diverging and converging neurodevelopmental trajectories of BD and ADHD.
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Affiliation(s)
- Hidayet Ece Arat Çelik
- Maltepe University, Faculty of Medicine, Department of Psychiatry, İstanbul, Turkey.,Dokuz Eylül University, Institute of Health Sciences, Department of Neuroscience, İzmir, Turkey
| | - Deniz Ceylan
- Koç University, Faculty of Medicine, Department of Psychiatry, İstanbul, Turkey
| | | | - Ayşe Erdoğan
- Dokuz Eylül University, Institute of Health Sciences, Department of Neuroscience, İzmir, Turkey
| | - Devran Tan
- Nişantaşı University, Faculty of Economics, Administrative and Scocial Sciences, Department of Psychology, İstanbul, Turkey
| | - Peren Gümüşkesen
- Dokuz Eylül University, Institute of Health Sciences, Department of Neuroscience, İzmir, Turkey
| | - Başak Bağci
- Katip Çelebi University, Ataturk Training and Research Hospital, Department of Psychiatry, İzmir, Turkey
| | - Ayşegül Özerdem
- Mayo Clinic, Department of Psychiatry and Psychology, Rochester, MN, USA
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Lineweaver TT, Kercood S, Gabor AJ, Cervantes J, Laine A, Baker E. The effect of medication and question wording on self-reported symptoms and their accuracy in young adults with attention-deficit/hyperactivity disorder. BRITISH JOURNAL OF CLINICAL PSYCHOLOGY 2021; 60:252-269. [PMID: 33393098 DOI: 10.1111/bjc.12276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 12/06/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVES This study examined the effect of whether participants were on or off their medications and the effect of questionnaire wording on self-reported symptoms in young adults with ADHD. Additionally, this research evaluated the relationships between these self-reported symptoms and objective performance on measures of working memory. DESIGN This experimental study utilized a mixed factorial design with one between-subjects factor (whether participants were unmedicated or medicated at the time they completed their assessment) and one within-subjects factor (whether participants reported their on-medication or off-medication symptoms when describing their ADHD subjective symptomatology). METHODS Forty-five young adults with ADHD (ages 18-23) completed a brief neuropsychological evaluation and several self-report questionnaires. RESULTS Although being medicated or unmedicated while completing the questionnaires did not directly affect self-reported symptoms or their accuracy, questionnaire wording exerted a statistically significant effect on subjective symptomatology; participants described themselves as substantially more symptomatic at times when they are off than at times when they are on their medications. More importantly, their general self-perceptions (symptoms when medication state was not specified) of their Inattention/Memory Problems and their Hyperactivity/Restlessness aligned with their descriptions of their off-medication symptoms, whereas their general self-perceptions of their Impulsivity/Emotional Lability and Problems with Self-Concept related to both their self-reported off-medication and on-medication symptoms. CONCLUSIONS These results highlight the necessity of specifying medication state when asking patients to report their current symptomatology. Failing to do so risks an over-reporting of symptoms from patients who are typically on medications as they may describe the extent of their unmedicated, rather than medicated, symptomatology. PRACTITIONER POINTS Being medicated or unmedicated while completing questionnaires about subjective symptomatology did not directly affect self-reported symptoms of young adults with ADHD or the accuracy of these self-reports. When medication state was not specified on a questionnaire, young adults with ADHD reported symptoms similar to those they experience when they are not medicated. These results highlight the importance of specifying medication state when asking young adults with ADHD to report their current symptomatology. Failing to do so risks an over-reporting of symptoms from patients who are typically on medications. These findings open the door for further research with larger and more diverse and representative samples of adults with ADHD to evaluate the accuracy of their subjective symptomatology relative to their objective abilities. Future studies should also examine whether gender affects subjective symptoms, their accuracy, or the influence of question wording and medications on self-reported symptomatology of adults with ADHD, as the current study was unable to address this important issue.
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Affiliation(s)
- Tara T Lineweaver
- Department of Psychology, Butler University, Indianapolis, Indiana, USA
| | - Suneeta Kercood
- College of Education, Butler University, Indianapolis, Indiana, USA
| | - Alexandra J Gabor
- Department of Psychology, Butler University, Indianapolis, Indiana, USA
| | - Jhovana Cervantes
- Department of Psychology, Butler University, Indianapolis, Indiana, USA
| | - Abigail Laine
- Department of Psychology, Butler University, Indianapolis, Indiana, USA
| | - Ellen Baker
- Department of Psychology, Butler University, Indianapolis, Indiana, USA
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Pironti VA, Vatansever D, Sahakian BJ. Shared alterations in resting-state brain connectivity in adults with attention-deficit/hyperactivity disorder and their unaffected first-degree relatives. Psychol Med 2021; 51:329-339. [PMID: 31769365 PMCID: PMC7893505 DOI: 10.1017/s0033291719003374] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 09/15/2019] [Accepted: 11/04/2019] [Indexed: 01/08/2023]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is a developmental condition that often persists into adulthood with extensive negative consequences on quality of life. Despite emerging evidence indicating the genetic basis of ADHD, investigations into the familial expression of latent neurocognitive traits remain limited. METHODS In a group of adult ADHD probands (n = 20), their unaffected first-degree relatives (n = 20) and typically developing control participants (n = 20), we assessed endophenotypic alterations in the default mode network (DMN) connectivity during resting-state functional magnetic resonance imaging in relation to cognitive performance and clinical symptoms. In an external validation step, we also examined the dimensional nature of this neurocognitive trait in a sample of unrelated healthy young adults (n = 100) from the Human Connectome Project (HCP). RESULTS The results illustrated reduced anti-correlations between the posterior cingulate cortex/precuneus and right middle frontal gyrus that was shared between adult ADHD probands and their first-degree relatives, but not with healthy controls. The observed connectivity alterations were linked to higher ADHD symptoms that was mediated by performance in a sustained attention task. Moreover, this brain-based neurocognitive trait dimensionally explained ADHD symptom variability in the HCP sample. CONCLUSIONS Alterations in the default mode connectivity may represent a dimensional endophenotype of ADHD, hence a significant aspect of the neuropathophysiology of this disorder. As such, brain network organisation can potentially be employed as an important neurocognitive trait to enhance statistical power of genetic studies in ADHD and as a surrogate efficacy endpoint in the development of novel pharmaceuticals.
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Affiliation(s)
- Valentino Antonio Pironti
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Suno Innova Ltd, Unit 6, 109 Cambridge Road Industrial Estate, Cambridge, UK
| | - Deniz Vatansever
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Institute of Science and Technology for Brain-inspired Intelligence, Fudan University, Shanghai, PR China
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Department of Psychology, University of York, Heslington, York, UK
| | - Barbara Jacquelyn Sahakian
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Institute of Science and Technology for Brain-inspired Intelligence, Fudan University, Shanghai, PR China
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Abstract
Nootropics are drugs used to either treat or benefit cognition deficits. Among this class, methylphenidate is a popular agent, which acts through indirect dopaminergic and noradrenergic agonism and, therefore, is proposed to enhance performance in catecholamine-dependent cognitive domains such as attention, memory and prefrontal cortex-dependent executive functions. However, investigation into the efficacy of methylphenidate as a cognitive enhancer has yielded variable results across all domains, leading to debate within the scientific community surrounding its off-label use in healthy individuals seeking scholaristic benefit or increased productivity. Through analysis of experimental data and methodological evaluation, it is apparent that there are dose-, task- and domain-dependent considerations surrounding the use of methylphenidate in healthy individuals, whereby tailored dose administration is likely to provide benefit on an individual basis dependent on the domain of cognition in which benefit is required. Additionally, it is apparent that there are subjective effects of methylphenidate, which may increase user productivity irrespective of cognitive benefit. Whilst there is not extensive study in healthy older adults, it is plausible that there are dose-dependent benefits to methylphenidate in older adults in selective cognitive domains that might improve quality of life and reduce fall risk. Methylphenidate appears to produce dose-dependent benefits to individuals with attention-deficit/hyperactivity disorder, but the evidence for benefit in Parkinson's disease and schizophrenia is inconclusive. As with any off-label use of pharmacological agents, and especially regarding drugs with neuromodulatory effects, there are inherent safety concerns; epidemiological and experimental evidence suggests there are sympathomimetic, cardiovascular and addictive considerations, which might further restrict their use within certain demographics.
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Gasanov RF, Makarov IV, Emelina DA. [Cognitive deficit in children with hyperkinetic disorder]. Zh Nevrol Psikhiatr Im S S Korsakova 2020; 120:126-131. [PMID: 32323954 DOI: 10.17116/jnevro2020120031126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The review presents current data on the nature of cognitive deficit in children with hyperkinetic disorder, and possible pathophysiological mechanisms of the disease. Considering possible neurobiological components of hyperkinetic disorder, attention is given to pathological functional connections underlying specific clinical manifestations of the disease.
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Affiliation(s)
- R F Gasanov
- Bekhterev National Research Medical Center for Psychiatry and Neurology, St. Peterburg, Russia
| | - I V Makarov
- Bekhterev National Research Medical Center for Psychiatry and Neurology, St. Peterburg, Russia.,Mechnicov North-Western State Medical University, St. Peterburg, Russia
| | - D A Emelina
- Bekhterev National Research Medical Center for Psychiatry and Neurology, St. Peterburg, Russia
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Effect of chronic methylphenidate treatment on hippocampal neurovascular unit and memory performance in late adolescent rats. Eur Neuropsychopharmacol 2019; 29:195-210. [PMID: 30554860 DOI: 10.1016/j.euroneuro.2018.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/13/2018] [Accepted: 12/01/2018] [Indexed: 12/21/2022]
Abstract
Methylphenidate (MPH) is the classic treatment for attention deficit hyperactivity disorder (ADHD) among children and adults. Despite its beneficial effects, non-medical use of MPH is nowadays a problem with high impact on society. Thus, our goal was to uncover the neurovascular and cognitive effects of MPH chronic use during a critical period of development in control conditions. For that, male Wistar Kyoto rats were treated with MPH (1.5 or 5 mg/kg/day at weekdays, per os) from P28 to P55. We concluded that the higher dose of MPH caused hippocampal blood-brain barrier (BBB) hyperpermeability by vesicular transport (transcytosis) concomitantly with the presence of peripheral immune cells in the brain parenchyma. These observations were confirmed by in vitro studies, in which the knockdown of caveolin-1 in human brain endothelial cells prevented the increased permeability and leukocytes transmigration triggered by MPH (100 µM, 24 h). Furthermore, MPH led to astrocytic atrophy and to a decrease in the levels of several synaptic proteins and impairment of AKT/CREB signaling, together with working memory deficit assessed in the Y-maze test. On the contrary, we verified that the lower dose of MPH (1.5 mg/kg/day) increased astrocytic processes and upregulated several neuronal proteins as well as signaling pathways involved in synaptic plasticity culminating in working memory improvement. In conclusion, the present study reveals that a lower dose of MPH in normal rats improves memory performance being associated with the modulation of astrocytic morphology and synaptic machinery. However, a higher dose of MPH leads to BBB dysfunction and memory impairment.
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Barnett M, Reid L. The effectiveness of methylphenidate in improving cognition after brain injury in adults: a systematic review. Brain Inj 2019; 34:1-10. [PMID: 31526025 DOI: 10.1080/02699052.2019.1667538] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Objective: To conduct a systematic review investigating the effectiveness of methylphenidate in improving cognition following brain injury in an adult population.Data sources: CINAHL, PsychINFO, MEDLINE, and PubMed databases were searched for all relevant articles published from January 1980 up to December 2017.Study selection: Studies were included if participants had a diagnosis of new onset or previous acquired brain injury and were age 16 or over. Studies must have administered methylphenidate and measured its effectiveness on cognition using at least one measure of cognitive function.Data extraction: Data extracted included study design, sample size, participant characteristics, intervention method, outcome measures, and findings. The quality of included randomized controlled trials was assessed using the Physiotherapy Evidence Database. An overall level of evidence was assigned using a modified Sackett scale.Data synthesis: Included studies consisted of seven randomized controlled trials, two pre-post trials, one prospective controlled trial, and one case study. All included studies reported improved cognitive abilities following methylphenidate treatment post-injury.Conclusions: There is the strongest level of evidence (Level 1a) suggesting methylphenidate may alleviate cognitive impairments in adults with brain injury. However, longitudinal studies are warranted examining the effectiveness and safety of long-term methylphenidate use in this population.
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Affiliation(s)
- Megan Barnett
- Brain Injury Rehabilitation Centre, Murdostoun Brain Injury Rehabilitation & Neurological Care Centre, Wishaw, Scotland
| | - Louise Reid
- Brain Injury Rehabilitation Centre, Murdostoun Brain Injury Rehabilitation & Neurological Care Centre, Wishaw, Scotland
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Basic processes as foundations of cognitive impairment in adult ADHD. J Neural Transm (Vienna) 2019; 126:1347-1362. [PMID: 31321549 PMCID: PMC6764934 DOI: 10.1007/s00702-019-02049-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 07/11/2019] [Indexed: 12/23/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) in adulthood is associated with impairment of multiple aspects of cognition which adversely affect the individual's everyday functioning. However, little is known about how these impairments are intertwined. This study explores whether impairments in basic processes (processing speed and distractibility) in adults with ADHD explain impairments in higher order functions, namely executive functions, memory, and complex attention. Furthermore, it is explored whether pharmacological treatment with methylphenidate (MPH) affects basic processes and higher order functions. A between-subjects design compared patients with ADHD without stimulant drug treatment (N = 55) and patients with ADHD treated with MPH (N = 31) with a healthy control group (N = 80). A neuropsychological test battery assessing basic processes and higher order functions was administered. Hierarchical logistic regression analyses were performed to evaluate the contribution of basic processes to impairments in higher order functions. Patients with ADHD not treated with MPH showed impairments in basic processes and higher order functions compared to controls. The impairments in basic processes explained 41-43% of impairments in executive functions, 27-29% in memory, and 56-74% in complex attention. In patients with ADHD treated with MPH, basic processes were not impaired and did not contribute significantly to impairments of higher order functions. Basic processes may constitute part of the foundation of cognitive impairments in adult ADHD. MPH may improve cognitive performance, presumably through improving basic processes. Applying this information could optimize neuropsychological assessments and inform treatment strategies by targeting basic processes.
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Vatansever D, Bozhilova NS, Asherson P, Smallwood J. The devil is in the detail: exploring the intrinsic neural mechanisms that link attention-deficit/hyperactivity disorder symptomatology to ongoing cognition. Psychol Med 2019; 49:1185-1194. [PMID: 30514410 DOI: 10.1017/s0033291718003598] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is a developmental condition that profoundly affects quality of life. Although mounting evidence now suggests uncontrolled mind-wandering as a core aspect of the attentional problems associated with ADHD, the neural mechanisms underpinning this deficit remains unclear. To that extent, competing views argue for (i) excessive generation of task-unrelated mental content, or (ii) deficiency in the control of task-relevant cognition. METHODS In a cross-sectional investigation of a large neurotypical cohort (n = 184), we examined alterations in the intrinsic brain functional connectivity architecture of the default mode (DMN) and frontoparietal (FPN) networks during resting state functional magnetic resonance imaging in relation to ADHD symptomatology, which could potentially underlie changes in ongoing thought within variable environmental contexts. RESULTS The results illustrated that ADHD symptoms were linked to lower levels of detail in ongoing thought while the participants made more difficult, memory based decisions. Moreover, greater ADHD scores were associated with lower levels of connectivity between the DMN and right sensorimotor cortex, and between the FPN and right ventral visual cortex. Finally, a combination of high levels of ADHD symptomology with reduced FPN connectivity to the visual cortex was associated with reduced levels of detail in thought. CONCLUSIONS The results of our study suggest that the frequent mind-wandering observed in ADHD may be an indirect consequence of the deficient control of ongoing cognition in response to increasing environmental demands, and that this may partly arise from dysfunctions in the intrinsic organisation of the FPN at rest.
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Affiliation(s)
| | - Natali S Bozhilova
- Social, Genetic and Developmental Psychiatry Centre, Psychology and Neuroscience, Institute of Psychiatry, King's College London,London,UK
| | - Philip Asherson
- Social, Genetic and Developmental Psychiatry Centre, Psychology and Neuroscience, Institute of Psychiatry, King's College London,London,UK
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11
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Pievsky MA, McGrath RE. Neurocognitive effects of methylphenidate in adults with attention-deficit/hyperactivity disorder: A meta-analysis. Neurosci Biobehav Rev 2018; 90:447-455. [DOI: 10.1016/j.neubiorev.2018.05.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 05/06/2018] [Accepted: 05/07/2018] [Indexed: 01/19/2023]
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Abstract
BACKGROUND Attention-deficit hyperactivity disorder (ADHD) is a common and impairing neurodevelopmental disorder. The Cambridge Neuropsychological Test Automated Battery (CANTAB) is a computerized test battery with standardized procedures and solid psychometric properties targeting multiple neuropsychological functions. AIMS The aim of this study was to look at the effects of ADHD on cognitive performance using CANTAB expressed as a statistical interaction term in regression modeling. METHODS We assessed 112 drug-naïve subjects (age: 7-18 years) with ADHD based on DSM IV criteria and compared them to 95 control subjects (age: 7-18 years). All participants were administered five CANTAB tasks designed to capture different aspects of executive functioning: Stockings of Cambridge (SOC), Intra/Extra dimensional shift (IED), Spatial Working Memory (SWM), Simple Reaction Time (SRT) and Stop Signal Task (SST). RESULTS T-tests showed a difference between ADHD and control subjects in all cognitive measures except SOC. The majority of measures showed a non-linear effect of age. SWM strategy and SST direction errors showed a linear effect of age. ADHD diagnosis had a statistically significant effect on performance. For all tests except SOC, ADHD produced the main effect without interaction with age. DISCUSSION For all CANTAB measures, ADHD diagnosis had a significant effect on performance and produced this effect without interaction with age in all tests except SOC, indicating that the developmental trajectories were parallel in both groups. The results indicate that cognitive performance is impaired in youth with ADHD and that CANTAB can be a valuable tool in the diagnostic assessment of ADHD.
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Affiliation(s)
- Emma Claesdotter
- a Department of Clinical Sciences Lund , Lund University , Lund , Sweden
| | - Matti Cervin
- a Department of Clinical Sciences Lund , Lund University , Lund , Sweden
| | - Sofia Åkerlund
- a Department of Clinical Sciences Lund , Lund University , Lund , Sweden
| | - Maria Råstam
- a Department of Clinical Sciences Lund , Lund University , Lund , Sweden.,b Department of Psychiatry and Neurochemistry, Gillberg Neuropsychiatry Centre , University of Gothenburg , Göteborg , Sweden
| | - Magnus Lindvall
- a Department of Clinical Sciences Lund , Lund University , Lund , Sweden
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13
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Klinge C, Shuttleworth C, Muglia P, Nobre AC, Harmer CJ, Murphy SE. Methylphenidate enhances implicit learning in healthy adults. J Psychopharmacol 2018; 32:70-80. [PMID: 28946787 DOI: 10.1177/0269881117731472] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND PURPOSE One limiting factor in the development of pharmacological interventions to enhance cognition is the absence of biomarkers that can be used in healthy volunteers to screen novel compounds. Drug discovery has tended to rely heavily on explicit measures of cognition, but these are typically insensitive to cognition-enhancing effects in healthy volunteers. This study investigated whether a novel battery of implicit cognition measures is sensitive to the effects of methylphenidate (Ritalin) in healthy volunteers. EXPERIMENTAL APPROACH Eighty healthy volunteers were randomised to receive either a single (10 mg) dose of methylphenidate or matched placebo. Participants completed a battery of tasks measuring implicit cognition (location priming, contextual cueing, implicit task switching). The effect of methylphenidate on standard, explicit measures of cognition was also assessed. KEY RESULTS Methylphenidate enhanced implicit learning on the location priming task and the implicit task-switching task. In line with previous work, we found that these effects were greater in male volunteers. There was no evidence for improved learning in any of the explicit measures. CONCLUSION AND IMPLICATIONS These results demonstrate that implicit measures of cognition are sensitive to pharmacological interventions in healthy volunteers. As such, implicit cognition measures may be a useful way of screening and tracking cognitive effects of novel agents in experimental medicine studies.
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Affiliation(s)
- Corinna Klinge
- 1 Department of Psychiatry, University of Oxford, Oxford, UK.,2 Oxford Health, NHS Foundation Trust, Oxford, UK
| | | | | | - Anna C Nobre
- 4 Oxford Centre for Human Brain Activity, University of Oxford, Oxford, UK.,5 Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Catherine J Harmer
- 1 Department of Psychiatry, University of Oxford, Oxford, UK.,2 Oxford Health, NHS Foundation Trust, Oxford, UK
| | - Susannah E Murphy
- 1 Department of Psychiatry, University of Oxford, Oxford, UK.,2 Oxford Health, NHS Foundation Trust, Oxford, UK
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Rubio Morell B, Hernández Expósito S. Differential long-term medication impact on executive function and delay aversion in ADHD. APPLIED NEUROPSYCHOLOGY-CHILD 2017; 8:140-157. [DOI: 10.1080/21622965.2017.1407653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Belen Rubio Morell
- Child Psychiatry Unit, Hospital Universitario de Canarias, La Laguna, Spain
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15
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Gardner RM, Yengo-Kahn A, Bonfield CM, Solomon GS. Comparison of baseline and post-concussion ImPACT test scores in young athletes with stimulant-treated and untreated ADHD. PHYSICIAN SPORTSMED 2017; 45:1-10. [PMID: 27736285 DOI: 10.1080/00913847.2017.1248221] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Baseline and post-concussion neurocognitive testing is useful in managing concussed athletes. Attention deficit hyperactivity disorder (ADHD) and stimulant medications are recognized as potential modifiers of performance on neurocognitive testing by the Concussion in Sport Group. Our goal was to assess whether individuals with ADHD perform differently on post-concussion testing and if this difference is related to the use of stimulants. METHODS Retrospective case-control study in which 4373 athletes underwent baseline and post-concussion testing using the ImPACT battery. 277 athletes self-reported a history of ADHD, of which, 206 reported no stimulant treatment and 69 reported stimulant treatment. Each group was matched with participants reporting no history of ADHD or stimulant use on several biopsychosocial characteristics. Non-parametric tests were used to assess ImPACT composite score differences between groups. RESULTS Participants with ADHD had worse verbal memory, visual memory, visual motor speed, and reaction time scores than matched controls at baseline and post-concussion, all with p ≤ .001 and |r|≥ 0.100. Athletes without stimulant treatment had lower verbal memory, visual memory, visual motor speed, and reaction time scores than controls at baseline (p ≤ 0.01, |r|≥ 0.100 [except verbal memory, r = -0.088]) and post-concussion (p = 0.000, |r|> 0.100). Athletes with stimulant treatment had lower verbal memory (Baseline: p = 0.047, r = -0.108; Post-concussion: p = 0.023, r = -0.124) and visual memory scores (Baseline: p = 0.013, r = -0.134; Post-concussion: p = 0.003, r = -0.162) but equivalent visual motor speed and reaction time scores versus controls at baseline and post-concussion. CONCLUSIONS ADHD-specific baseline and post-concussion neuropsychological profiles, as well as stimulant medication status, may need to be considered when interpreting ImPACT test results. Further investigation into the effects of ADHD and stimulant use on recovery from sport-related concussion (SRC) is warranted.
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Affiliation(s)
- Ryan M Gardner
- a Vanderbilt Sports Concussion Center , Vanderbilt University School of Medicine , Nashville , TN , USA
| | - Aaron Yengo-Kahn
- a Vanderbilt Sports Concussion Center , Vanderbilt University School of Medicine , Nashville , TN , USA.,b Department of Neurological Surgery , Vanderbilt University School of Medicine , Nashville , TN , USA
| | - Christopher M Bonfield
- a Vanderbilt Sports Concussion Center , Vanderbilt University School of Medicine , Nashville , TN , USA.,b Department of Neurological Surgery , Vanderbilt University School of Medicine , Nashville , TN , USA
| | - Gary S Solomon
- a Vanderbilt Sports Concussion Center , Vanderbilt University School of Medicine , Nashville , TN , USA.,b Department of Neurological Surgery , Vanderbilt University School of Medicine , Nashville , TN , USA
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Spiegelstein O, Stevens J, Van Gerven J, Nathan PJ, Maynard JP, Mayleben DW, Hellriegel E, Yang R. Pharmacokinetics, pharmacodynamics and safety of CEP-26401, a high-affinity histamine-3 receptor antagonist, following single and multiple dosing in healthy subjects. J Psychopharmacol 2016; 30:983-93. [PMID: 27222271 DOI: 10.1177/0269881116645301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
CEP-26401 is a novel orally active, brain-penetrant, high-affinity histamine H3 receptor (H3R) antagonist, with potential therapeutic utility in cognition enhancement. Two randomized, double-blind, placebo-controlled dose escalation studies with single (0.02 to 5 mg) or multiple administration (0.02 to 0.5 mg once daily) of CEP-26401 were conducted in healthy subjects. Plasma and urine samples were collected to investigate CEP-26401 pharmacokinetics. Pharmacodynamic endpoints included a subset of tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB) and nocturnal polysomnography. Population pharmacokinetic-pharmacodynamic modeling was conducted on one CANTAB and one polysomnography parameter of interest. CEP-26401 was slowly absorbed (median tmax range 3-6 hours) and the mean terminal elimination half-life ranged from 24-60 hours. Steady-state plasma concentrations were achieved within six days of dosing. CEP-26401 exhibits dose- and time-independent pharmacokinetics, and renal excretion is a major elimination pathway. CEP-26401 had a dose-dependent negative effect on sleep, with some positive effects on certain CANTAB cognitive parameters seen at lower concentrations. The derived three compartment population pharmacokinetic model, with first-order absorption and elimination, accurately described the available pharmacokinetic data. CEP-26401 was generally well tolerated up to 0.5 mg/day with most common treatment related adverse events being headache and insomnia. Further clinical studies are required to establish the potential of low-dose CEP-26401 in cognition enhancement.
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Affiliation(s)
| | | | | | - Pradeep J Nathan
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | | | | | - Edward Hellriegel
- Research and Development Teva Pharmaceuticals, West Chester, PA, USA
| | - Ronghua Yang
- Research and Development Teva Pharmaceuticals, West Chester, PA, USA
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17
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Pironti VA, Lai MC, Morein-Zamir S, Müller U, Bullmore ET, Sahakian BJ. Temporal reproduction and its neuroanatomical correlates in adults with attention deficit hyperactivity disorder and their unaffected first-degree relatives. Psychol Med 2016; 46:2561-2569. [PMID: 27345441 DOI: 10.1017/s003329171600101x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Little is known about time perception, its putative role as cognitive endophenotype, and its neuroanatomical underpinnings in adults with attention deficit hyperactivity disorder (ADHD). METHOD Twenty adults with ADHD, 20 unaffected first-degree relatives and 20 typically developing controls matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional grey-matter volumes. Temporal processing was investigated as a putative cognitive endophenotype using a temporal reproduction paradigm. General linear modelling was employed to examine the relationship between temporal reproduction performances and grey-matter volumes. RESULTS ADHD participants were impaired in temporal reproduction and unaffected first-degree relatives performed in between their ADHD probands and typically developing controls. Increased grey-matter volume in the cerebellum was associated with poorer temporal reproduction performance. CONCLUSIONS Adults with ADHD are impaired in time reproduction. Performances of the unaffected first-degree relatives are in between ADHD relatives and controls, suggesting that time reproduction might be a cognitive endophenotype for adult ADHD. The cerebellum is involved in time reproduction and might play a role in driving time performances.
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Affiliation(s)
- V A Pironti
- Department of Psychiatry,University of Cambridge,Herschel Smith Building for Brain and Mind Sciences,Cambridge Biomedical Campus,Cambridge,UK
| | - M-C Lai
- Department of Psychiatry,National Taiwan University Hospital and College of Medicine,Taipei,Taiwan
| | - S Morein-Zamir
- Department of Psychiatry,University of Cambridge,Herschel Smith Building for Brain and Mind Sciences,Cambridge Biomedical Campus,Cambridge,UK
| | - U Müller
- Department of Psychiatry,University of Cambridge,Herschel Smith Building for Brain and Mind Sciences,Cambridge Biomedical Campus,Cambridge,UK
| | - E T Bullmore
- Department of Psychiatry,University of Cambridge,Herschel Smith Building for Brain and Mind Sciences,Cambridge Biomedical Campus,Cambridge,UK
| | - B J Sahakian
- Department of Psychiatry,University of Cambridge,Herschel Smith Building for Brain and Mind Sciences,Cambridge Biomedical Campus,Cambridge,UK
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18
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Tamminga HGH, Reneman L, Huizenga HM, Geurts HM. Effects of methylphenidate on executive functioning in attention-deficit/hyperactivity disorder across the lifespan: a meta-regression analysis. Psychol Med 2016; 46:1791-1807. [PMID: 27019103 DOI: 10.1017/s0033291716000350] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) in childhood and adulthood is often treated with the psychostimulant methylphenidate (MPH). However, it is unknown whether cognitive effects of MPH depend on age in individuals with ADHD, while animal studies have suggested age-related effects. In this meta-analysis, we first determined the effects of MPH on response inhibition, working memory and sustained attention, but our main goal was to examine whether these effects are moderated by age. A systematic literature search using PubMed, PsycINFO, Web of Science and MEDLINE for double-blind, placebo-controlled studies with MPH resulted in 25 studies on response inhibition (n = 775), 13 studies on working memory (n = 559) and 29 studies on sustained attention (n = 956) (mean age range 4.8-50.1 years). The effects of MPH on response inhibition [effect size (ES) = 0.40, p < 0.0001, 95% confidence interval (CI) 0.22-0.58], working memory (ES = 0.24, p = 0.053, 95% CI 0.00-0.48) and sustained attention (ES = 0.42, p < 0.0001, 95% CI 26-0.59) were small to moderate. No linear or quadratic age-dependencies were observed, indicating that effects of MPH on executive functions are independent of age in children and adults with ADHD. However, adolescent studies are lacking and needed to conclude a lack of an age-dependency across the lifespan.
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Affiliation(s)
- H G H Tamminga
- Department of Radiology,Academic Medical Center Amsterdam,Amsterdam,The Netherlands
| | - L Reneman
- Department of Radiology,Academic Medical Center Amsterdam,Amsterdam,The Netherlands
| | - H M Huizenga
- Department of Psychology,University of Amsterdam,Amsterdam,The Netherlands
| | - H M Geurts
- Department of Psychology,University of Amsterdam,Amsterdam,The Netherlands
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19
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Batistela S, Bueno OFA, Vaz LJ, Galduróz JCF. Methylphenidate as a cognitive enhancer in healthy young people. Dement Neuropsychol 2016; 10:134-142. [PMID: 29213444 PMCID: PMC5642404 DOI: 10.1590/s1980-5764-2016dn1002009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The so-called cognitive enhancers have been widely and increasingly used by healthy individuals who seek improvements in cognitive performance despite having no pathologies. One drug used for this purpose is methylphenidate, a first-line drug for the treatment of attention deficit hyperactivity disorder (ADHD). Objective The aim of the present study was to test the effect of acute administration of varying doses of methylphenidate (10 mg, 20 mg, 40 mg and placebo) on a wide range of cognitive functions in healthy young people. Methods A total of 36 young university students and graduates participated in the study. The participants underwent tests of attention and of episodic, and working memory. Results No differences in performance were observed on any of the tests. There was a dose-dependent (40 mg > placebo) effect on self-reported wellbeing. Conclusions According to the recent literature, psychostimulant medications, such as methylphenidate, improve performance when cognitive processes are below an optimal level, which was not the case for the subjects of the present study. We suggest the impression that methylphenidate enhances cognitive performance in healthy young people, justifying its use, may be due to improvements in subjective wellbeing promoted by the drug.
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Affiliation(s)
- Silmara Batistela
- MS, Departamento de Psicobiologia - Universidade Federal de São Paulo, São Paulo SP, Brazil
| | | | - Leonardo José Vaz
- PhD,Departamento de Psicobiologia - Universidade Federal de São Paulo, São Paulo SP, Brazil
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20
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Ni HC, Hwang Gu SL, Lin HY, Lin YJ, Yang LK, Huang HC, Gau SSF. Atomoxetine could improve intra-individual variability in drug-naïve adults with attention-deficit/hyperactivity disorder comparably with methylphenidate: A head-to-head randomized clinical trial. J Psychopharmacol 2016; 30:459-67. [PMID: 26905919 DOI: 10.1177/0269881116632377] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Intra-individual variability in reaction time (IIV-RT) is common in individuals with attention-deficit/hyperactivity disorder (ADHD). It can be improved by stimulants. However, the effects of atomoxetine on IIV-RT are inconclusive. We aimed to investigate the effects of atomoxetine on IIV-RT, and directly compared its efficacy with methylphenidate in adults with ADHD. METHODS An 8-10 week, open-label, head-to-head, randomized clinical trial was conducted in 52 drug-naïve adults with ADHD, who were randomly assigned to two treatment groups: immediate-release methylphenidate (n=26) thrice daily (10-20 mg per dose) and atomoxetine once daily (n=26) (0.5-1.2 mg/kg/day). IIV-RT, derived from the Conners' continuous performance test (CCPT), was represented by the Gaussian (reaction time standard error, RTSE) and ex-Gaussian models (sigma and tau). Other neuropsychological functions, including response errors and mean of reaction time, were also measured. Participants received CCPT assessments at baseline and week 8-10 (60.4±6.3 days). RESULTS We found comparable improvements in performances of CCPT between the immediate-release methylphenidate- and atomoxetine-treated groups. Both medications significantly improved IIV-RT in terms of reducing tau values with comparable efficacy. In addition, both medications significantly improved inhibitory control by reducing commission errors. CONCLUSION Our results provide evidence to support that atomoxetine could improve IIV-RT and inhibitory control, of comparable efficacy with immediate-release methylphenidate, in drug-naïve adults with ADHD. Shared and unique mechanisms underpinning these medication effects on IIV-RT awaits further investigation.
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Affiliation(s)
- Hsing-Chang Ni
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan Department of Psychiatry, Chang Gung Memorial Hospital at Linkou, Taiwan
| | - Shoou-Lian Hwang Gu
- Graduate Institute of Behavioral Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Hsiang-Yuan Lin
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Ju Lin
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan Department of Psychiatry, Far Eastern Memorial Hospital, Taipei, Taiwan Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Li-Kuang Yang
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan Department of Psychiatry, Beitou Branch, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hui-Chun Huang
- Department of Child and Adolescent Psychiatry, Taoyaun Psychiatric Center, Ministry of Health and Welfare, Taoyuan County, Taiwan
| | - Susan Shur-Fen Gau
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan
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21
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Fuermaier ABM, Tucha L, Koerts J, Weisbrod M, Lange KW, Aschenbrenner S, Tucha O. Effects of methylphenidate on memory functions of adults with ADHD. APPLIED NEUROPSYCHOLOGY-ADULT 2016; 24:199-211. [DOI: 10.1080/23279095.2015.1124108] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Anselm B. M. Fuermaier
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands
| | - Lara Tucha
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands
| | - Janneke Koerts
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands
| | - Matthias Weisbrod
- Department of Psychiatry and Psychotherapy, SRH Clinic Karlsbad-Langensteinbach, Karlsbad-Langensteinbach, Germany
- Section for Experimental Psychopathology, Centre for Psychosocial Medicine, University of Heidelberg, Heidelberg, Germany
| | - Klaus W. Lange
- Department of Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Steffen Aschenbrenner
- Department of Clinical Psychology and Neuropsychology, SRH Clinic Karlsbad-Langensteinbach, Karlsbad-Langensteinbach, Germany
| | - Oliver Tucha
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands
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22
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Sofuoglu M, DeVito EE, Waters AJ, Carroll KM. Cognitive Function as a Transdiagnostic Treatment Target in Stimulant Use Disorders. J Dual Diagn 2016; 12:90-106. [PMID: 26828702 PMCID: PMC4837011 DOI: 10.1080/15504263.2016.1146383] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Stimulant use disorder is an important public health problem, with an estimated 2.1 million current users in the United States alone. No pharmacological treatments are approved by the U.S. Food and Drug Administration for stimulant use disorder and behavioral treatments have variable efficacy and limited availability. Most individuals with stimulant use disorder have other comorbidities, most with overlapping symptoms and cognitive impairments. The goal of this article is to present a rationale for cognition as a treatment target in stimulant use disorder and to outline potential treatment approaches. Rates of lifetime comorbid psychiatric disorders among people with stimulant use disorders are estimated at 65% to 73%, with the most common being mood disorders (13% to 64%) and anxiety disorders (21% to 50%), as well as non-substance-induced psychotic disorders (<10%). There are several models of addictive behavior, but the dual process model particularly highlights the relevance of cognitive impairments and biases to the development and maintenance of addiction. This model explains addictive behavior as a balance between automatic processes and executive control, which in turn are related to individual (genetics, comorbid disorders, psychosocial factors) and other (craving, triggers, drug use) factors. Certain cognitive impairments, such as attentional bias and approach bias, are most relevant to automatic processes, while sustained attention, response inhibition, and working memory are primarily related to executive control. These cognitive impairments and biases are also common in disorders frequently comorbid with stimulant use disorder and predict poor treatment retention and clinical outcomes. As such, they may serve as feasible transdiagnostic treatment targets. There are promising pharmacological, cognitive, and behavioral approaches that aim to enhance cognitive function. Pharmacotherapies target cognitive impairments associated with executive control and include cholinesterase inhibitors (e.g., galantamine, rivastigmine) and monoamine transporter inhibitors (e.g., modafinil, methylphenidate). Cognitive behavioral therapy and cognitive rehabilitation also enhance executive control, while cognitive bias modification targets impairments associated with automatic processes. Cognitive enhancement to improve treatment outcomes is a novel and promising strategy, but its clinical value for the treatment of stimulant use disorder, with or without other psychiatric comorbidities, remains to be determined in future studies.
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Affiliation(s)
- Mehmet Sofuoglu
- a Department of Psychiatry , Yale University School of Medicine , West Haven , Connecticut , USA.,b VA Connecticut Healthcare System , West Haven , Connecticut , USA
| | - Elise E DeVito
- a Department of Psychiatry , Yale University School of Medicine , West Haven , Connecticut , USA.,b VA Connecticut Healthcare System , West Haven , Connecticut , USA
| | - Andrew J Waters
- c Department of Medical and Clinical Psychology , Uniformed Services University of the Health Science , Bethesda , Maryland , USA
| | - Kathleen M Carroll
- a Department of Psychiatry , Yale University School of Medicine , West Haven , Connecticut , USA.,b VA Connecticut Healthcare System , West Haven , Connecticut , USA
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23
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Mostert JC, Onnink AMH, Klein M, Dammers J, Harneit A, Schulten T, van Hulzen KJE, Kan CC, Slaats-Willemse D, Buitelaar JK, Franke B, Hoogman M. Cognitive heterogeneity in adult attention deficit/hyperactivity disorder: A systematic analysis of neuropsychological measurements. Eur Neuropsychopharmacol 2015; 25:2062-2074. [PMID: 26336867 PMCID: PMC4788979 DOI: 10.1016/j.euroneuro.2015.08.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 08/03/2015] [Accepted: 08/13/2015] [Indexed: 02/04/2023]
Abstract
Attention Deficit/Hyperactivity Disorder (ADHD) in childhood is associated with impaired functioning in multiple cognitive domains: executive functioning (EF), reward and timing. Similar impairments have been described for adults with persistent ADHD, but an extensive investigation of neuropsychological functioning in a large sample of adult patients is currently lacking. We systematically examined neuropsychological performance on tasks measuring EF, delay discounting, time estimation and response variability using univariate ANCOVA's comparing patients with persistent ADHD (N=133, 42% male, mean age 36) and healthy adults (N=132, 40% male, mean age 36). In addition, we tested which combination of variables provided the highest accuracy in predicting ADHD diagnosis. We also estimated for each individual the severity of neuropsychological dysfunctioning. Lastly, we investigated potential effects of stimulant medication and a history of comorbid major depressive disorder (MDD) on performance. Compared to healthy adults, patients with ADHD showed impaired EF, were more impulsive, and more variable in responding. However, effect sizes were small to moderate (range: 0.05-0.70) and 11% of patients did not show neuropsychological dysfunctioning. The best fitting model predicting ADHD included measures from distinct cognitive domains (82.1% specificity, 64.9% sensitivity). Furthermore, patients receiving stimulant medication or with a history of MDD were not distinctively impaired. To conclude, while adults with ADHD as a group are impaired on several cognitive domains, the results confirm that adult ADHD is neuropsychologically heterogeneous. This provides a starting point to investigate individual differences in terms of impaired cognitive pathways.
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Affiliation(s)
- Jeanette C Mostert
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands.,Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - A Marten H Onnink
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Marieke Klein
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | - Janneke Dammers
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands.,Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Anais Harneit
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | - Theresa Schulten
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | - Kimm J E van Hulzen
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands.,Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Cornelis C Kan
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | | | - Jan K Buitelaar
- Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, The Netherlands.,Department of Cognitive Neurosciences, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Barbara Franke
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands.,Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Martine Hoogman
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
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24
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Remission Rate and Functional Outcomes During a 6-Month Treatment With Osmotic-Release Oral-System Methylphenidate in Children With Attention-Deficit/Hyperactivity Disorder. J Clin Psychopharmacol 2015; 35:525-34. [PMID: 26267421 DOI: 10.1097/jcp.0000000000000389] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Many definitions have been used to evaluate remission in patients with attention-deficit/hyperactivity disorder (ADHD) in different studies resulting with varied remission rates. This open-label, multicenter study investigated the remission rate in Chinese children (n = 239; aged 6-16 years) with a diagnosis of ADHD (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), treated with osmotic-release oral-system methylphenidate at doses of 18, 36, and 54 mg, once daily. Two definitions of remission were used: (1) (primary end point): average scores of SNAP-IV (Swanson, Nolan, and Pelham, Fourth Edition) items of 1 or less (0-3 rating scale for each item) according to the subtype of ADHD (inattentive [1-9], hyperactive-impulsive [10-18], and combined type [1-18]), and (2) total score of SNAP-IV items 1 to 18 of 18 or less, at week 8. The study consisted of screening/baseline, titration/open-label treatment (8 weeks), and extended observation (up to 24 weeks) phases. Secondary efficacy assessments were Clinical Global Impression-Improvement (clinical efficacy), Behavior Rating Inventory of Executive Function Scale (BRIEF; executive function behaviors), and Weiss Functional Impairment Rating Scale (social function). Validity of remission was assessed by comparing the function measures (BRIEF and Weiss's) between patients who achieved remission and those who did not. At week 8, 69.3% (151/218) of patients achieved remission by definition 1, and 73.2% (161/220) by definition 2. At weeks 8 and 24, the remission group had significantly lower BRIEF, Weiss's, and Clinical Global Impression-Improvement scores (P < 0.001 for all) compared with the nonremission group. Overall, treatment with osmotic-release oral-system methylphenidate was well tolerated, with increased remission rates in children with ADHD.
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25
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Sahakian BJ, Bruhl AB, Cook J, Killikelly C, Savulich G, Piercy T, Hafizi S, Perez J, Fernandez-Egea E, Suckling J, Jones PB. The impact of neuroscience on society: cognitive enhancement in neuropsychiatric disorders and in healthy people. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140214. [PMID: 26240429 PMCID: PMC4528826 DOI: 10.1098/rstb.2014.0214] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2015] [Indexed: 01/23/2023] Open
Abstract
In addition to causing distress and disability to the individual, neuropsychiatric disorders are also extremely expensive to society and governments. These disorders are both common and debilitating and impact on cognition, functionality and wellbeing. Cognitive enhancing drugs, such as cholinesterase inhibitors and methylphenidate, are used to treat cognitive dysfunction in Alzheimer's disease and attention deficit hyperactivity disorder, respectively. Other cognitive enhancers include specific computerized cognitive training and devices. An example of a novel form of cognitive enhancement using the technological advancement of a game on an iPad that also acts to increase motivation is presented. Cognitive enhancing drugs, such as methylphenidate and modafinil, which were developed as treatments, are increasingly being used by healthy people. Modafinil not only affects 'cold' cognition, but also improves 'hot' cognition, such as emotion recognition and task-related motivation. The lifestyle use of 'smart drugs' raises both safety concerns as well as ethical issues, including coercion and increasing disparity in society. As a society, we need to consider which forms of cognitive enhancement (e.g. pharmacological, exercise, lifelong learning) are acceptable and for which groups (e.g. military, doctors) under what conditions (e.g. war, shift work) and by what methods we would wish to improve and flourish.
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Affiliation(s)
- Barbara J Sahakian
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
| | - Annette B Bruhl
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032 Zurich, Switzerland
| | - Jennifer Cook
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK
| | - Clare Killikelly
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK
| | - George Savulich
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK
| | - Thomas Piercy
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK
| | - Sepehr Hafizi
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK CAMEO North Team, 3 Thorpe Road, Peterborough PE3 6AN, UK
| | - Jesus Perez
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK CAMEO South Team, Block 7, Ida Darwin Site, Fulbourn, Cambridge CB21 5EE, UK
| | - Emilio Fernandez-Egea
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
| | - John Suckling
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
| | - Peter B Jones
- Department of Psychiatry, University of Cambridge, Herchel Smith Building for Brain and Mind Sciences, Forvie Site, Robinson Way, Cambridge CB2 0SZ, UK MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
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26
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Vanicek T, Spies M, Rami-Mark C, Savli M, Höflich A, Kranz GS, Hahn A, Kutzelnigg A, Traub-Weidinger T, Mitterhauser M, Wadsak W, Hacker M, Volkow ND, Kasper S, Lanzenberger R. The norepinephrine transporter in attention-deficit/hyperactivity disorder investigated with positron emission tomography. JAMA Psychiatry 2014; 71:1340-1349. [PMID: 25338091 PMCID: PMC4699255 DOI: 10.1001/jamapsychiatry.2014.1226] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
IMPORTANCE Attention-deficit/hyperactivity disorder (ADHD) research has long focused on the dopaminergic system's contribution to pathogenesis, although the results have been inconclusive. However, a case has been made for the involvement of the noradrenergic system, which modulates cognitive processes, such as arousal, working memory, and response inhibition, all of which are typically affected in ADHD. Furthermore, the norepinephrine transporter (NET) is an important target for frequently prescribed medication in ADHD. Therefore, the NET is suggested to play a critical role in ADHD. OBJECTIVE To explore the differences in NET nondisplaceable binding potential (NET BPND) using positron emission tomography and the highly selective radioligand (S,S)-[18F]FMeNER-D2 [(S,S)-2-(α-(2-[18F]fluoro[2H2]methoxyphenoxy)benzyl)morpholine] between adults with ADHD and healthy volunteers serving as controls. DESIGN, SETTING, AND PARTICIPANTS Twenty-two medication-free patients with ADHD (mean [SD] age, 30.7 [10.4] years; 15 [68%] men) without psychiatric comorbidities and 22 age- and sex-matched healthy controls (30.9 [10.6] years; 15 [68%] men) underwent positron emission tomography once. A linear mixed model was used to compare NET BPND between groups. MAIN OUTCOMES AND MEASURES The NET BPND in selected regions of interest relevant for ADHD, including the hippocampus, putamen, pallidum, thalamus, midbrain with pons (comprising a region of interest that includes the locus coeruleus), and cerebellum. In addition, the NET BPND was evaluated in thalamic subnuclei (13 atlas-based regions of interest). RESULTS We found no significant differences in NET availability or regional distribution between patients with ADHD and healthy controls in all investigated brain regions (F1,41<0.01; P=.96). Furthermore, we identified no significant association between ADHD symptom severity and regional NET availability. Neither sex nor smoking status influenced NET availability. We determined a significant negative correlation between age and NET availability in the thalamus (R2=0.29; P<.01 corrected) and midbrain with pons, including the locus coeruleus (R2=0.18; P<.01 corrected), which corroborates prior findings of a decrease in NET availability with aging in the human brain. CONCLUSIONS AND RELEVANCE Our results do not indicate involvement of changes in brain NET availability or distribution in the pathogenesis of ADHD. However, the noradrenergic transmitter system may be affected on a different level, such as in cortical regions, which cannot be reliably quantified with this positron emission tomography ligand. Alternatively, different key proteins of noradrenergic neurotransmission might be affected.
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Affiliation(s)
- Thomas Vanicek
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Marie Spies
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Christina Rami-Mark
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Markus Savli
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Anna Höflich
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Georg S. Kranz
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Andreas Hahn
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Alexandra Kutzelnigg
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Tatjana Traub-Weidinger
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Markus Mitterhauser
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Wadsak
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Nora D. Volkow
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
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Pironti VA, Lai MC, Müller U, Dodds CM, Suckling J, Bullmore ET, Sahakian BJ. Neuroanatomical abnormalities and cognitive impairments are shared by adults with attention-deficit/hyperactivity disorder and their unaffected first-degree relatives. Biol Psychiatry 2014; 76:639-47. [PMID: 24199662 PMCID: PMC4183379 DOI: 10.1016/j.biopsych.2013.09.025] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/28/2013] [Accepted: 09/03/2013] [Indexed: 12/24/2022]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder, yet the search for genes with a definitive role in its etiology has been elusive. Deconstructing the disorder in its endophenotypic traits, where the variance is thought to be associated with a fewer number of genes, should boost the statistical power of molecular genetic studies and clarify the pathophysiology of ADHD. In this study, we tested for neuroanatomical and cognitive endophenotypes in a group of adults with ADHD, their unaffected first-degree relatives, and typically developing control subjects. METHODS Sixty participants, comprising 20 adults with ADHD, 20 unaffected first-degree relatives, and 20 typically developing control subjects matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional gray and white matter volumes. General linear analyses of the volumes of brain regions, adjusting for age and total intracranial volume, were used to compare groups. Sustained attention and response inhibition were also investigated as cognitive endophenotypes. RESULTS Neuroanatomical abnormalities in gray matter volume in the right inferior frontal gyrus and white matter volume in the caudal portion of the right inferior fronto-occipital fasciculus were shared between ADHD probands and their unaffected first-degree relatives. In addition, impairments in sustained attention were also found to be shared between ADHD patients and their relatives. CONCLUSIONS Cognitive impairments in sustained attention and neuroanatomical abnormalities in the right inferior frontal gyrus and the posterior part of right inferior fronto-occipital fasciculus are putative neurocognitive endophenotypes in adult ADHD.
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Affiliation(s)
- Valentino Antonio Pironti
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Medical Research Council/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Adult ADHD Clinic, Cambridgeshire & Peterborough National Health Service Foundation Trust, Cambridge, United Kingdom.
| | - Meng-Chuan Lai
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ulrich Müller
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Adult ADHD Clinic, Cambridgeshire & Peterborough National Health Service Foundation Trust, Cambridge, United Kingdom
| | - Chris Martin Dodds
- Department of Psychology, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - John Suckling
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Medical Research Council/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Edward Thomas Bullmore
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Medical Research Council/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Barbara Jacquelyn Sahakian
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Medical Research Council/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Adult ADHD Clinic, Cambridgeshire & Peterborough National Health Service Foundation Trust, Cambridge, United Kingdom
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28
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Yabuki Y, Shioda N, Maeda T, Hiraide S, Togashi H, Fukunaga K. Aberrant CaMKII activity in the medial prefrontal cortex is associated with cognitive dysfunction in ADHD model rats. Brain Res 2014; 1557:90-100. [DOI: 10.1016/j.brainres.2014.02.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/21/2014] [Accepted: 02/12/2014] [Indexed: 01/11/2023]
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Methylphenidate enhances cognitive performance in adults with poor baseline capacities regardless of attention-deficit/hyperactivity disorder diagnosis. J Clin Psychopharmacol 2014; 34:261-5. [PMID: 24525641 DOI: 10.1097/jcp.0000000000000076] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We compare the view that the effect of methylphenidate (MPH) is selective to individuals with attention-deficit/hyperactivity disorder (ADHD) with an alternative approach suggesting that its effect is more prominent for individuals with weak baseline capacities in relevant cognitive tasks. To evaluate theses 2 approaches, we administered sustained attention, working memory, and decision-making tasks to 20 ADHD adults and 19 control subjects, using a within-subject placebo-controlled design. The results demonstrated no main effects of MPH in the decision-making tasks. In the sustained attention and working-memory tasks, MPH enhanced performance of both ADHD and non-ADHD adults to a similar extent compared with placebo. Hence, the effect of MPH was not selective to ADHD adults. In addition, those benefitting most from MPH in all 3 task domains tended to be individuals with poor task performance. However, in most tasks, individuals whose performance was impaired by MPH were not necessarily better (or worse) performers. The findings suggest that the administration of MPH to adults with ADHD should consider not only clinical diagnosis but also their functional (performance-based) profile.
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30
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Jan RK, Lin JC, McLaren DG, Kirk IJ, Kydd RR, Russell BR. The effects of methylphenidate on cognitive control in active methamphetamine dependence using functional magnetic resonance imaging. Front Psychiatry 2014; 5:20. [PMID: 24639656 PMCID: PMC3944404 DOI: 10.3389/fpsyt.2014.00020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/07/2014] [Indexed: 01/28/2023] Open
Abstract
Methamphetamine (MA) dependence is associated with cognitive deficits. Methylphenidate (MPH) has been shown to improve inhibitory control in healthy and cocaine-dependent subjects. This study aimed to understand the neurophysiological effects before and after acute MPH administration in active MA-dependent and control subjects. Fifteen MA-dependent and 18 control subjects aged 18-46 years were scanned using functional magnetic resonance imaging before and after either a single oral dose of MPH (18 mg) or placebo while performing a color-word Stroop task. Baseline accuracy was lower (p = 0.026) and response time (RT) was longer (p < 0.0001) for the incongruent compared to congruent condition, demonstrating the task probed cognitive control. Increased activation of the dorsolateral prefrontal cortex (DLPFC) and parietal cortex during the incongruent and Stroop effect conditions, respectively was observed in MA-dependent compared to control subjects (p < 0.05), suggesting the need to recruit neural resources within these regions for conflict resolution. Post- compared to pre-MPH treatment, increased RT and DLPFC activation for the Stroop effect were observed in MA-dependent subjects (p < 0.05). In comparison to MPH-treated controls and placebo-treated MA-dependent subjects, MPH-treated MA-dependent subjects showed decreased activation of parietal and occipital regions during the incongruent and Stroop effect conditions (p < 0.05). These findings suggest that in MA-dependent subjects, MPH facilitated increased recruitment of the DLPFC for Stroop conflict resolution, and a decreased need for recruitment of neural resources in parietal and occipital regions compared to the other groups, while maintaining a comparable level of task performance to that achieved pre-drug administration. Due to the small sample size, the results from this study are preliminary; however, they inform us about the effects of MPH on the neural correlates of cognitive control in active MA-dependent subjects.
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Affiliation(s)
- Reem K Jan
- School of Pharmacy, University of Auckland , Auckland , New Zealand ; Centre for Brain Research, University of Auckland , Auckland , New Zealand
| | - Joanne C Lin
- School of Pharmacy, University of Auckland , Auckland , New Zealand ; Centre for Brain Research, University of Auckland , Auckland , New Zealand
| | - Donald G McLaren
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital , Boston, MA , USA ; Department of Neurology, Massachusetts General Hospital , Boston, MA , USA ; Harvard Medical School , Boston, MA , USA
| | - Ian J Kirk
- Centre for Brain Research, University of Auckland , Auckland , New Zealand ; Department of Psychology, University of Auckland , Auckland , New Zealand
| | - Rob R Kydd
- Centre for Brain Research, University of Auckland , Auckland , New Zealand ; Department of Psychological Medicine, University of Auckland , Auckland , New Zealand
| | - Bruce R Russell
- School of Pharmacy, University of Auckland , Auckland , New Zealand ; Centre for Brain Research, University of Auckland , Auckland , New Zealand
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31
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del Campo N, Fryer TD, Hong YT, Smith R, Brichard L, Acosta-Cabronero J, Chamberlain SR, Tait R, Izquierdo D, Regenthal R, Dowson J, Suckling J, Baron JC, Aigbirhio FI, Robbins TW, Sahakian BJ, Müller U. A positron emission tomography study of nigro-striatal dopaminergic mechanisms underlying attention: implications for ADHD and its treatment. ACTA ACUST UNITED AC 2013; 136:3252-70. [PMID: 24163364 PMCID: PMC4125626 DOI: 10.1093/brain/awt263] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Through the combined use of 18F-fallypride positron emission tomography and magnetic resonance imaging this study examined the neural mechanisms underlying the attentional deficits associated with attention deficit/hyperactivity disorder and their potential reversal with a single therapeutic dose of methylphenidate. Sixteen adult patients with attention deficit/hyperactivity disorder and 16 matched healthy control subjects were positron emission tomography and magnetic resonance imaging scanned and tested on a computerized sustained attention task after oral methylphenidate (0.5 mg/kg) and placebo administration in a within-subject, double-blind, cross-over design. Although patients with attention deficit/hyperactivity disorder as a group showed significant attentional deficits and reduced grey matter volume in fronto-striato-cerebellar and limbic networks, they had equivalent D2/D3 receptor availability and equivalent increases in endogenous dopamine after methylphenidate treatment to that observed in healthy control subjects. However, poor attentional performers drawn from both the attention deficit/hyperactivity disorder and the control groups had significantly reduced left caudate dopamine activity. Methylphenidate significantly increased dopamine levels in all nigro-striatal regions, thereby normalizing dopamine levels in the left caudate in low performers. Behaviourally, methylphenidate improved sustained attention in a baseline performance-dependent manner, irrespective of diagnosis. This finding was accompanied by an equally performance-dependent effect of the drug on dopamine release in the midbrain, whereby low performers showed reduced dopamine release in this region. Collectively, these findings support a dimensional model of attentional deficits and underlying nigro-striatal dopaminergic mechanisms of attention deficit/hyperactivity disorder that extends into the healthy population. Moreover, they confer midbrain dopamine autoreceptors a hitherto neglected role in the therapeutic effects of oral methylphenidate in attention deficit/hyperactivity disorder. The absence of significant case–control differences in D2/D3 receptor availability (despite the observed relationships between dopamine activity and attention) suggests that dopamine dysregulation per se is unlikely to be the primary cause underlying attention deficit/hyperactivity disorder pathology in adults. This conclusion is reinforced by evidence of neuroanatomical changes in the same set of patients with attention deficit/hyperactivity disorder.
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Affiliation(s)
- Natalia del Campo
- 1 Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
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A head-to-head randomized clinical trial of methylphenidate and atomoxetine treatment for executive function in adults with attention-deficit hyperactivity disorder. Int J Neuropsychopharmacol 2013; 16:1959-73. [PMID: 23672818 DOI: 10.1017/s1461145713000357] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Results regarding the effects of methylphenidate and atomoxetine on executive functions were inconsistent and no study has directly compared the efficacy of these two medications in improving executive functions in adults with attention-deficit hyperactivity disorder (ADHD). We conducted an 8-10 wk, open-label, head-to-head, randomized clinical trial involving adults with a clinical diagnosis of ADHD confirmed by psychiatric interview. The two treatment arms were immediate-release methylphenidate (IR-methylphenidate) (n = 31) and atomoxetine once daily (n = 32). Executive functions were assessed by the Cambridge Neuropsychological Test Automated Battery (CANTAB), including spatial working memory, spatial span, intra-extra dimensional set shifts, rapid visual information processing and Stockings of Cambridge (SOC). In addition to the symptom assessments at baseline (week 0), visit 2 (week 4-5) and visit 3 (week 8–10), they received CANTAB assessments at baseline and visit 3 (60.4 ± 6.3 d). Compared to baseline, adults treated with atomoxetine showed significant improvement in spatial working memory, spatial short-term memory, sustained attention and spatial planning at visit 3; adults treated with IR-methylphenidate showed significant improvement in spatial working memory at visit 3. Comparing the magnitude of improvement in executive functions between these two medications, the effect was generally similar for the two groups, although atomoxetine might have significantly greater efficacy than IR-methylphenidate in terms of improving spatial planning (SOC). Our results provide evidence to support that both IR-methylphenidate and atomoxetine improved various executive functions in adults with ADHD with greater improvement in atomoxetine than IR-methylphenidate in spatial planning.
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33
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Neurocircuitry underlying the preferential sensitivity of prefrontal catecholamines to low-dose psychostimulants. Neuropsychopharmacology 2013; 38:1078-84. [PMID: 23303075 PMCID: PMC3629407 DOI: 10.1038/npp.2013.6] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Low doses of psychostimulants, including methylphenidate (MPH), are highly effective in the treatment of attention-deficit/hyperactivity disorder (ADHD). At these doses, psychostimulants improve prefrontal cortex (PFC)-dependent function. Recent evidence indicates that low and clinically relevant doses of psychostimulants target norepinephrine (NE) and dopamine (DA) signaling preferentially in the PFC. To better understand the neural mechanisms responsible for the regional selectivity of low-dose psychostimulant action, it is important to first identify the underlying neurocircuitry. The current study used reverse microdialysis to test the hypothesis that the preferential targeting of PFC catecholamines by low-dose psychostimulants involves direct action within the PFC, reflecting an intrinsic property of this region. For these studies, the effects of varying concentrations of MPH (0.25, 1.0, and 4.0 μM) on NE and DA efflux were examined within the PFC and select subcortical fields in unanesthetized rats. Low concentrations of MPH elicited significantly larger increases in extracellular levels of NE and DA in the PFC than in subcortical regions linked to motor-activating and arousal-promoting actions of psychostimulants (nucleus accumbens and medial septal area, respectively). The differential action of MPH across regions disappeared at higher concentrations. The enhanced sensitivity of PFC catecholamines to low and clinically relevant doses of psychostimulants, at least in part, reflects a unique sensitivity of this region to NE/DA transporter blockade. Available evidence suggests that the increased sensitivity of PFC catecholamines likely involves DA clearance through the NE transporter within the PFC.
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34
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Tai YM, Gau SSF, Gau CS. Injury-proneness of youth with attention-deficit hyperactivity disorder: a national clinical data analysis in Taiwan. RESEARCH IN DEVELOPMENTAL DISABILITIES 2013; 34:1100-1108. [PMID: 23340027 DOI: 10.1016/j.ridd.2012.11.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/28/2012] [Accepted: 11/28/2012] [Indexed: 06/01/2023]
Abstract
Limited literature documents injury-proneness of attention-deficit hyperactivity disorder in western population. However, only a few studies prospectively investigated the prediction of ADHD to injuries without considering other psychiatric and physical conditions and there is lack of such data in Asian population. To prospectively examine the prediction of ADHD to the risk of injury in a national sample of Taiwan, we conducted this study with samples including 1965 6-18-year-old youths with newly diagnosis of ADHD from 1999 to 2003, and 7860 sex-, age- and index day-matched non-ADHD controls from Taiwan's National Health Insurance Research Database (1997-2008). Relevant psychiatric and physical disorders, demographics, and medications were also included in the Cox proportional hazard models with injury as the outcome. Our results showed that ADHD cases had a roughly 2-fold and 5-fold higher risk of each injury, and overall injury than controls after considering all confounding factors, respectively. In addition to ADHD, use of anxiolytics, antidepressants, and antipsychotics, and comorbid physical illnesses also predicted the injury prospectively. Our findings strongly support that ADHD predicted injury risks and imply that physicians should take the risk of injury into consideration while prescribing medications other than stimulants to patients with ADHD, especially anxiolytics.
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Affiliation(s)
- Yueh-Ming Tai
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan
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35
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Holstein DH, Vollenweider FX, Geyer MA, Csomor PA, Belser N, Eich D. Sensory and sensorimotor gating in adult attention-deficit/hyperactivity disorder (ADHD). Psychiatry Res 2013; 205:117-26. [PMID: 23017654 DOI: 10.1016/j.psychres.2012.08.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 07/30/2012] [Accepted: 08/10/2012] [Indexed: 12/15/2022]
Abstract
Even though there is an impaired perceptual capacity in attention-deficit/hyperactivity disorder (ADHD) patients, psychophysiological alterations, such as impaired gating as indexed by prepulse inhibition (PPI) or suppression of P50 auditory event-related potentials, have not been found in patients with ADHD. Hence, potential relationships of psychophysiological measures of gating to psychopathology and cognitive performance remain unclear. The present study investigates two distinct operational measures of gating as well as cognitive performance within adult ADHD patients in order to assess the relationship of these measures to psychopathology. PPI, P50 suppression, cognitive performance, and psychopathologic symptoms were assessed in 26 ADHD patients and 26 healthy control subjects. ADHD patients compared to healthy control subjects exhibited impaired P50 suppression, performed worse in cognitive tasks, and reported more psychopathological symptoms, but were normal in the test of PPI. Thus, P50 gating deficits are not specific to schizophrenia-spectrum disorders. These findings highlight the differences between P50 gating and PPI as measures of the gating construct. In keeping with the lack of correlations between these two putative operational measures of gating seen in both humans and animals, adult ADHD patients exhibit deficient P50 suppression and poor cognitive performance, despite exhibiting normal levels of PPI.
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Affiliation(s)
- Dominique H Holstein
- Psychiatric University Hospital of Psychiatry Zurich, PO Box 1932, CH-8032 Zurich, Switzerland.
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36
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Sofuoglu M, DeVito EE, Waters AJ, Carroll KM. Cognitive enhancement as a treatment for drug addictions. Neuropharmacology 2013; 64:452-63. [PMID: 22735770 PMCID: PMC3445733 DOI: 10.1016/j.neuropharm.2012.06.021] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 06/12/2012] [Accepted: 06/13/2012] [Indexed: 02/04/2023]
Abstract
Drug addiction continues to be an important public health problem, with an estimated 22.6 million current illicit drug users in the United States alone. For many addictions, including cocaine, methamphetamine, and marijuana addiction, there are no approved pharmacological treatments. Behavioral treatments are effective but effects vary widely across individuals. Treatments that are effective across multiple addictions are greatly needed, and accumulating evidence suggests that one such approach may be pharmacological or behavioral interventions that enhance executive inhibitory control in addicts. Current evidence indicates that most forms of chronic drug use may be associated with significant cognitive impairments, especially in attention, working memory, and response inhibition functions. In some studies, these impairments predict poor treatment retention and outcome. A number of cognitive enhancing agents, including galantamine, modafinil, atomoxetine, methylphenidate, and guanfacine, have shown promising findings in human studies. Specific behavioral interventions, including cognitive remediation, also show promise. However, whether improvement of selective cognitive functions reduces drug use behavior remains to be determined. Cognitive enhancement to improve treatment outcomes is a novel strategy worthy of future research, as are related questions such as whether these approaches may be broadly beneficial to most addicts or best reserved for substance users with specific demonstrated cognitive impairments. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Mehmet Sofuoglu
- Yale University, School of Medicine, Department of Psychiatry, VA Connecticut Healthcare System, 950 Campbell Ave., Bldg. 36/116A4, West Haven, CT 06516, USA.
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Berridge CW, Arnsten AFT. Psychostimulants and motivated behavior: arousal and cognition. Neurosci Biobehav Rev 2012; 37:1976-84. [PMID: 23164814 DOI: 10.1016/j.neubiorev.2012.11.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 10/19/2012] [Accepted: 11/05/2012] [Indexed: 12/11/2022]
Abstract
Motivated, goal-directed behavior requires the coordination of multiple behavioral processes that facilitate interacting with the environment, including arousal, motivation, and executive function. Psychostimulants exert potent modulatory influences on these processes, providing a useful tool for understanding the neurobiology of motivated behavior. The neural mechanisms underlying the reinforcing effects of psychostimulants have been extensively studied over the past 50 years. In contrast, the study of the neurobiology of the arousal-enhancing and executive-modulating actions of psychostimulants was only initiated relatively recently. This latter work identifies a series of dose-dependent actions of psychostimulants within a network of prefrontal cortical and subcortical sites that coordinate the arousal-promoting and cognition-modulating effects of these drugs. These actions are dependent on a variety of catecholamine receptor subtypes, including noradrenergic α1 and α2 receptors and dopaminergic D1 receptors. In the prefrontal cortex, psychostimulants exert inverted-U shaped modulatory actions that are apparent at the levels of the neuron and behavior. Collectively, these observations provide new insight into the neurobiology underlying motivated, goal-directed behavior.
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Affiliation(s)
- Craig W Berridge
- Department of Psychology, University of Wisconsin, Madison, WI, United States.
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Lineweaver TT, Kercood S, O'Keeffe NB, O'Brien KM, Massey EJ, Campbell SJ, Pierce JN. The effects of distraction and a brief intervention on auditory and visual-spatial working memory in college students with attention deficit hyperactivity disorder. J Clin Exp Neuropsychol 2012; 34:791-805. [DOI: 10.1080/13803395.2012.683854] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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A selective dopamine reuptake inhibitor improves prefrontal cortex-dependent cognitive function: potential relevance to attention deficit hyperactivity disorder. Neuropharmacology 2012; 64:321-8. [PMID: 22796428 DOI: 10.1016/j.neuropharm.2012.07.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 06/28/2012] [Accepted: 07/03/2012] [Indexed: 11/21/2022]
Abstract
Drugs used to treat attention deficit hyperactivity disorder (ADHD) improve prefrontal cortex (PFC)-dependent cognitive function. The majority of ADHD-related treatments act either as dual norepinephrine (NE) and dopamine (DA) reuptake inhibitors (psychostimulants) or selective NE reuptake inhibitors (SNRIs). Certain benztropine analogs act as highly selective DA reuptake inhibitors while lacking the reinforcing actions, and thus abuse potential, of psychostimulants. To assess the potential use of these compounds in the treatment of ADHD, we examined the effects of a well-characterized benztropine analog, AHN 2-005, on performance of rats in a PFC-dependent delayed-alternation task of spatial working memory. Similar to that seen with all drugs currently approved for ADHD, AHN 2-005 dose-dependently improved performance in this task. Clinically-relevant doses of psychostimulants and SNRIs elevate NE and DA preferentially in the PFC. Despite the selectivity of this compound for the DA transporter, additional microdialysis studies demonstrated that a cognition-enhancing dose of AHN 2-005 that lacked locomotor activating effects increased extracellular levels of both DA and NE in the PFC. AHN 2-005 produced a larger increase in extracellular DA in the nucleus accumbens, although the magnitude of this was well below that seen with motor activating doses of psychostimulants. Collectively, these observations suggest that benztropine analogs may be efficacious in the treatment of ADHD or other disorders associated with PFC dysfunction. These studies provide a strong rationale for future research focused on the neural mechanisms contributing to the cognition-enhancing actions and the potential clinical utility of AHN 2-005 and related compounds. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Methylphenidate modulates sustained attention and cortical activation in survivors of traumatic brain injury: a perfusion fMRI study. Psychopharmacology (Berl) 2012; 222:47-57. [PMID: 22203319 PMCID: PMC3369011 DOI: 10.1007/s00213-011-2622-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 12/13/2011] [Indexed: 10/14/2022]
Abstract
RATIONALE Methylphenidate (MPH), the most widely prescribed psychostimulant to treat many neuropsychiatric conditions, is reported to improve attention and speed of processing in survivors of traumatic brain injury (TBI). The neural correlate of this efficacy, however, remains unclear. OBJECTIVE Using perfusion functional magnetic resonance imaging (fMRI) as a biomarker of regional neural activity, the current study aimed to examine the neural correlates of single-dose (0.3 mg/kg) MPH administration in a randomized double-blind placebo-controlled crossover study design. METHODS Twenty-three individuals with moderate to severe TBI were tested on two occasions approximately 1 week apart. Perfusion fMRI scanning was carried out at rest and while participants performed cognitive tasks requiring sustained attention and working memory. RESULTS Behaviorally, MPH significantly improved both accuracy and reaction time (RT) in the sustained attention task but only RT in the working memory task. A trend of global reduction of cerebral blood flow by MPH was observed in all task conditions including resting. Voxel-wise whole-brain analysis revealed an interaction effect of drug by condition (MPH-placebo X task-rest) for the sustained attention task in the left posterior superior parietal cortex and parieto-occipital junction (BA 7/19). The magnitude of drug-related deactivation of this area during task performance was correlated with improvement in RT. CONCLUSION Suppression of activity in this area during task performance may reflect a compensatory mechanism by which MPH ameliorates attention impairments in TBI.
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Dalley JW, Roiser JP. Dopamine, serotonin and impulsivity. Neuroscience 2012; 215:42-58. [PMID: 22542672 DOI: 10.1016/j.neuroscience.2012.03.065] [Citation(s) in RCA: 278] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 03/08/2012] [Accepted: 03/10/2012] [Indexed: 12/17/2022]
Abstract
Impulsive people have a strong urge to act without thinking. It is sometimes regarded as a positive trait but rash impulsiveness is also widely present in clinical disorders such as attention deficit hyperactivity disorder (ADHD), drug dependence, mania, and antisocial behaviour. Contemporary research has begun to make major inroads into unravelling the brain mechanisms underlying impulsive behaviour with a prominent focus on the limbic cortico-striatal systems. With this progress has come the understanding that impulsivity is a multi-faceted behavioural trait involving neurally and psychologically diverse elements. We discuss the significance of this heterogeneity for clinical disorders expressing impulsive behaviour and the pivotal contribution made by the brain dopamine and serotonin systems in the aetiology and treatment of behavioural syndromes expressing impulsive symptoms.
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Affiliation(s)
- J W Dalley
- Behavioural and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK. jwd20@cam. ac. uk
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Comparative study of OROS-MPH and atomoxetine on executive function improvement in ADHD: a randomized controlled trial. Int J Neuropsychopharmacol 2012; 15:15-26. [PMID: 22017969 DOI: 10.1017/s1461145711001490] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This study aimed to compare the effects of osmotic release oral system-methylphenidate (OROS-MPH) and atomoxetine (ATX) on executive function in children and adolescents with attention deficit hyperactivity disorder (ADHD) by a randomized controlled trial. Subjects who met DSM-IV ADHD criteria were randomized to receive either OROS-MPH or ATX treatment. The doses were titrated to achieve optimal response and then maintained for 4-6 wk. A battery of executive function tests and the Behavior Rating Inventory of Executive Function (BRIEF) were administered to subjects who completed the dose titration (OROS-MPH, n=85; ATX, n=57) at the pre- and post-treatment periods. Forty-six children without ADHD were recruited as controls. Both OROS-MPH and ATX significantly improved scores in the Rey Complex Figure Test (RCFT), digit span, and Stroop color-word task. The scores in RCFT and the reverse digit span were not significantly different from the control group at post-treatment assessment (OROS-MPH=ATX=control, p>0.05), whereas the word interference time of the Stroop test was still more than that of the control group (OROS-MPH=ATX>control, p>0.05). OROS-MPH also significantly improved the total correct response in the verbal fluency test to normal level, and the shifting time in the trail-making test to subnormal level. The current findings suggest both OROS-MPH and ATX improved executive function generally in children and adolescents with ADHD, and could return working memory back to normative performance level.
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Swanson JM, Wigal TL, Volkow ND. Contrast of medical and nonmedical use of stimulant drugs, basis for the distinction, and risk of addiction: comment on Smith and Farah (2011). Psychol Bull 2012; 137:742-8. [PMID: 21859175 DOI: 10.1037/a0024898] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Smith and Farah (2011) presented a scholarly review of critical areas related to their intriguing title "Are Prescription Stimulants 'Smart Pills'?" We contend that they accomplished the main goal of the article, to get the facts straight about possible cognitive enhancement via the nonmedical use of stimulant drugs by individuals without a diagnosis of attention-deficit/hyperactivity disorder (ADHD). At the same time, they justified their main conclusions that (a) individuals are seeking and engaging in nonmedical use of stimulant drugs with the expectations of cognitive enhancement despite uncertainty whether such expectations are valid and (b) on some tasks, there are small average benefits of nonmedical use, but the overall pattern is not clear (e.g., small beneficial effects across most individuals or large beneficial effects only in a few individuals, both of which result in small average effects). We offer comments in 3 areas to amplify key topics mentioned but not emphasized by Smith and Farah: (a) characterization of the cognitive effects of medical use of stimulants to contrast with the cognitive effects of nonmedical use; (b) justification of medical use of stimulants by placement on a normally distributed dimension of behavior rather than categorical diagnosis of ADHD, which varies widely across countries; and (c) evaluation of the potential risks of nonmedical use to individuals and to society (e.g., the likelihood of addiction to stimulant drugs in a small minority of the population) rather than just the potential benefits of cognitive enhancement.
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Abstract
In recent years, descriptive symptom-based approaches of attention deficit hyperactivity disorder (ADHD) have been increasingly replaced by more sophisticated endophenotype-based strategies, better suited to investigate its pathophysiological basis, which is inherently heterogeneous. Measurements derived from neuroimaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI) constitute endophenotypes of growing interest, capable of providing unprecedented windows on neurochemical and neuroanatomical components of psychiatric conditions. This chapter reviews the current state of knowledge regarding putative neural and behavioral endophenotypes of ADHD, across the lifespan. To this end, recent evidence drawn from molecular and structural neuroimaging studies are discussed in the light of widely accepted neuropsychological and pharmacological models of ADHD.
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Affiliation(s)
- Natalia del Campo
- Department of Psychiatry, and Behavioral and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK,
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Freese L, Signor L, Machado C, Ferigolo M, Barros HMT. Non-medical use of methylphenidate: a review. TRENDS IN PSYCHIATRY AND PSYCHOTHERAPY 2012; 34:110-5. [DOI: 10.1590/s2237-60892012000200010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 11/11/2011] [Indexed: 11/21/2022]
Abstract
INTRODUCTION: Methylphenidate is a psychostimulant medication used for the treatment of attention deficit hyperactivity disorder and narcolepsy. However, it has also been used for non-medical purposes, e.g. to produce euphoria, to increase self-esteem, and to achieve the so-called neurocognitive enhancement, decreasing the feeling of tiredness and increasing focus and attention. OBJECTIVE: To describe, from theoretical and contextual points of view, the potential for abuse and non-medical use of methylphenidate. METHOD: The PubMed, SciELO and Cochrane databases were searched using the following keywords in Portuguese: metilfenidato, transtorno do déficit de atenção com hiperatividade, facilitadores dos processos cognitivos or agentes nootrópicos, and abuso de substâncias; and in English: methylphenidate, attention deficit disorder with hyperactivity, cognitive enhancement or nootropic agents, and substance abuse. Studies published between 1990 and 2010 were selected for review. RESULTS: Non-medical use of methylphenidate is a relevant topic that raises important ethical and scientific questions in several areas, e.g. pharmacological and neurobiological characteristics, evidence of methylphenidate use, forms of non-medical use of methylphenidate, mechanisms of action, and therapeutic application of methylphenidate. According to the review, methylphenidate can generally influence performance as a result of its stimulatory effect. Notwithstanding, evidence does not support the conclusion that it can enhance cognitive performance. CONCLUSION: Health professionals need to acquire expert knowledge and inform patients and their families on the methylphenidate potential for abuse when used with non-medical purposes.
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Rucklidge JJ, Harrison R, Johnstone J. Can Micronutrients Improve Neurocognitive Functioning in Adults with ADHD and Severe Mood Dysregulation? A Pilot Study. J Altern Complement Med 2011; 17:1125-31. [DOI: 10.1089/acm.2010.0499] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Julia J. Rucklidge
- Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - Rachel Harrison
- Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - Jeanette Johnstone
- Department of Psychology, University of Canterbury, Christchurch, New Zealand
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Looby A, Earleywine M. Expectation to receive methylphenidate enhances subjective arousal but not cognitive performance. Exp Clin Psychopharmacol 2011; 19:433-44. [PMID: 21875224 PMCID: PMC3590067 DOI: 10.1037/a0025252] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nonmedical use of prescription-stimulant medication such as methylphenidate (MPH) has increased among college students over the past several years. Common motivations for use include enhancements in cognition and subjective arousal. As it is unclear whether stimulant medication exerts the same effect on healthy individuals as for those with attention-deficit/hyperactivity disorder, it is possible that many reported effects of prescription stimulants by healthy individuals may stem from placebo effects, which may be an important mechanism underlying initiation and maintenance of nonmedical use. This study examined whether placebo effects influence reports of subjective mood and cognitive performance among college students who endorsed several risk factors for prescription-stimulant misuse (i.e., low grade point average, fraternity/sorority involvement, binge drinking, cannabis use). Ninety-six subjects (60% male) completed cognitive tests and questionnaires assessing present mood state on two occasions. Forty-seven participants were randomized to an experimental condition and orally ingested what they believed to be MPH, though actually placebo, on one visit and received no medication on the other visit. The control group received no medication on either visit. During the administration visit, experimental participants reported feeling significantly more high and stimulated compared with the nonadministration visit and to the control subjects. However, cognitive enhancement differences were not generally seen between visits or groups. This research demonstrates that placebo effects for prescription stimulants do influence subjective mood and may be implicated in nonmedical stimulant use. This knowledge may be useful in challenging prescription-stimulant-related expectancies to decrease the prevalence of use among college students.
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Affiliation(s)
- Alison Looby
- Department of Psychology, University at Albany, State University of New York, USA.
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Chamberlain SR, Robbins TW, Winder-Rhodes S, Müller U, Sahakian BJ, Blackwell AD, Barnett JH. Translational approaches to frontostriatal dysfunction in attention-deficit/hyperactivity disorder using a computerized neuropsychological battery. Biol Psychiatry 2011; 69:1192-203. [PMID: 21047621 DOI: 10.1016/j.biopsych.2010.08.019] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 08/10/2010] [Accepted: 08/11/2010] [Indexed: 01/28/2023]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a prevalent condition associated with cognitive dysfunction. The Cambridge Neuropsychological Test Automated Battery is a computerized set of tests that has been widely used in ADHD and in translation/back-translation. Following a survey of translational research relevant to ADHD in experimental animals, a comprehensive literature review was conducted of studies that had used core Cambridge Neuropsychological Test Automated Battery tests 1) to evaluate cognitive dysfunction in ADHD and 2) to evaluate effects of salient drugs in patients and in volunteers. Meta-analysis was conducted where four or more independent datasets were available. Meta-analysis revealed medium-large decrements in ADHD for response inhibition (d = .790, p < .001), working memory (d = .883, p < .001), executive planning (d = .491, p < .001), and a small decrement in attentional set shifting (d = .160, p = .040). Qualitative review of the literature showed some consistent patterns. In ADHD, methylphenidate improved working memory, modafinil improved planning, and methylphenidate, modafinil, and atomoxetine improved inhibition. Meta-analysis of modafinil healthy volunteer studies showed no effects on sustained attention or set shifting. Results were paralleled by findings in experimental animals on comparable tests, enabling further analysis of drug mechanisms. Substantial cognitive deficits are present in ADHD, which can be remediated somewhat with current medications and which can readily be modeled in experimental animals using back-translational methodology. The findings suggest overlapping but also distinct early cognitive effects of ADHD medications and have important implications for understanding the pathophysiology of ADHD and for future trials.
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Affiliation(s)
- Samuel R Chamberlain
- Department of Psychiatry and Medical Research Council/Wellcome Trust Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom.
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The roles of dopamine and noradrenaline in the pathophysiology and treatment of attention-deficit/hyperactivity disorder. Biol Psychiatry 2011; 69:e145-57. [PMID: 21550021 DOI: 10.1016/j.biopsych.2011.02.036] [Citation(s) in RCA: 403] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 01/16/2011] [Accepted: 02/15/2011] [Indexed: 12/14/2022]
Abstract
Through neuromodulatory influences over fronto-striato-cerebellar circuits, dopamine and noradrenaline play important roles in high-level executive functions often reported to be impaired in attention-deficit/hyperactivity disorder (ADHD). Medications used in the treatment of ADHD (including methylphenidate, dextroamphetamine and atomoxetine) act to increase brain catecholamine levels. However, the precise prefrontal cortical and subcortical mechanisms by which these agents exert their therapeutic effects remain to be fully specified. Herein, we review and discuss the present state of knowledge regarding the roles of dopamine (DA) and noradrenaline in the regulation of corticostriatal circuits, with a focus on the molecular neuroimaging literature (both in ADHD patients and in healthy subjects). Recent positron emission tomography evidence has highlighted the utility of quantifying DA markers, at baseline or following drug administration, in striatal subregions governed by differential cortical connectivity. This approach opens the possibility of characterizing the neurobiological underpinnings of ADHD (and associated cognitive dysfunction) and its treatment by targeting specific neural circuits. It is anticipated that the application of refined and novel positron emission tomography methodology will help to disentangle the overlapping and dissociable contributions of DA and noradrenaline in the prefrontal cortex, thereby aiding our understanding of ADHD and facilitating new treatments.
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Barnes JJM, Dean AJ, Nandam LS, O'Connell RG, Bellgrove MA. The molecular genetics of executive function: role of monoamine system genes. Biol Psychiatry 2011; 69:e127-43. [PMID: 21397212 DOI: 10.1016/j.biopsych.2010.12.040] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 11/25/2010] [Accepted: 12/17/2010] [Indexed: 12/20/2022]
Abstract
Executive control processes, such as sustained attention, response inhibition, and error monitoring, allow humans to guide behavior in appropriate, flexible, and adaptive ways. The consequences of executive dysfunction for humans can be dramatic, as exemplified by the large range of both neurologic and neuropsychiatric disorders in which such deficits negatively affect outcome and quality of life. Much evidence suggests that many clinical disorders marked by executive deficits are highly heritable and that individual differences in quantitative measures of executive function are strongly driven by genetic differences. Accordingly, intense research effort has recently been directed toward mapping the genetic architecture of executive control processes in both clinical (e.g., attention-deficit/hyperactivity disorder) and nonclinical populations. Here we review the extant literature on the molecular genetic correlates of three exemplar but dissociable executive functions: sustained attention, response inhibition, and error processing. Our review focuses on monoaminergic gene variants given the strong body of evidence from cognitive neuroscience and pharmacology implicating dopamine, noradrenaline, and serotonin as neuromodulators of executive function. Associations between DNA variants of the dopamine beta hydroxylase gene and measures of sustained attention accord well with cognitive-neuroanatomical models of sustained attention. Equally, functional variants of the dopamine D2 receptor gene are reliably associated with performance monitoring, error processing, and reinforcement learning. Emerging evidence suggests that variants of the dopamine transporter gene (DAT1) and dopamine D4 receptor gene (DRD4) show promise for explaining significant variance in individual differences in both behavioral and neural measures of inhibitory control.
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Affiliation(s)
- Jessica J M Barnes
- Queensland Brain Institute and School of Psychology, University of Queensland, Brisbane, Australia
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