Synaptic gating and ADHD: a biological theory of comorbidity of ADHD and anxiety

Combined EEG-tDCS approach in resting state to reduce comorbid anxiety and depressive symptoms in affective disorders: A sham-controlled pilot study

Continuous challenges have been imposed on mental health science by Anxiety and Depression disorders as the most prevalent and debilitating psychiatric conditions worldwide. Pharmacologic and cognitive behavioral therapies, either alone or in combination, have been considered as the first-line therapies, however, resistant symptomatology is prevalent in comorbid conditions with symptoms remaining after interventions. The demand for new therapeutic solutions has given space to the development of non-invasive brain stimulation techniques (NIBS), and the transmagnetic direct current stimulation (tDCS) has been reported as a safe and well-tolerated technique for the treatment of several mental health conditions, including Anxiety and Depression disorders. Relying on quantitative electroencephalography(qEEG)- tDCS approach, the current study aims to inspect the effect of tDCS intervention on patients who suffer from anxiety-depression comorbidity, in particular, the impact of tDCS intervention on qEEG spectral power activity and resting-state connectivity organization during eyes closed and eyes open protocols. QEEG data were acquired from eight patients suffering from moderate to severe anxiety-depression comorbid symptoms along with poor coping skills to manage stress and negative affect. Twelve control subjects allocated in the control group exhibiting low to moderate symptoms in both anxiety and depression conditions went also through the qEEG data acquisition. In addition, a sham-controlled study was conducted, and the patient group went through resting-state qEEG-tDCS neuromodulation once a week for ten weeks. Various-stage qEEG recordings were performed to inspect the efficacy of tDCS treatment during the modulation of brain regions involved in the regulation of affective responses. Our results demonstrated that after tDCS neuromodulation, the patients' groups exhibited decreased absolute power abnormalities over the left anterior cingulate cortex and reduced abnormal activity in the alpha band over posterior regions; improved functional connectivity indexes; decreased anxiety and depressive scores while positive affect score was improved. Besides the promising improvements, our study did not find a significant tDCS effect on perceived stress and negative affect scores. Consistently, significant differences in absolute spectral power over the left anterior cingulate cortex were detected among the patient group, as compared to the controls, as expected. Therefore, our study offers preliminary data to understand the neuroplasticity changes that potentially result from the manipulation of cortical excitability during affective regulation protocols followed by the consequent decrease of comorbid anxiety and depressive symptomatology. The pilot study was followed by prospective registration with ChiCTR2200062142.

Development of a human-analogue, 3-symptom domain Dog ADHD and Functionality Rating Scale (DAFRS)

The family dog, in its natural environment, exhibits neuropsychological deficits redolent of human psychiatric disorders, including behaviours that are similar to human attention-deficit/hyperactivity disorder (ADHD) symptoms. Based on standard questionnaire methods in humans, we aimed to develop and validate a detailed, psychometrically improved tool to assess owner views on relevant dog behaviours. We modified available questionnaires by adding items that allow for separate analysis of impulsivity, and items on functional impairment. We collected data from 1168 owners for different validation steps of the new questionnaire and, similarly to assessment of humans where teachers also evaluate as an expert control, we collected data from dog trainers. Exploratory and confirmatory factor analysis revealed 3 factors: inattention (IA), hyperactivity (H) and impulsivity (I), corresponding to all three human symptom dimensions in dogs. Test-retest analyses showed excellent agreement between measurements for all factors. Similarly to findings with humans, trainer-owner rating comparisons showed fair (IA) to moderate (H, I) agreement. As in humans, greater ADHD scores were associated with greater functional impairment scores. We suggest that in dogs, similarly to humans, parallel examination of (extreme) ADHD and functional impairment scores could help distinguish diagnosable individuals, after further validation of the questionnaire using a relevant behaviour test.

P2X4 signalling contributes to hyperactivity but not pain sensitization comorbidity in a mouse model of attention deficit/hyperactivity disorder

Introduction: Attention deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterized by hyperactivity, inattention, and impulsivity that often persist until adulthood. Frequent comorbid disorders accompany ADHD and two thirds of children diagnosed with ADHD also suffer from behavioural disorders and from alteration of sensory processing. We recently characterized the comorbidity between ADHD-like symptoms and pain sensitisation in a pharmacological mouse model of ADHD, and we demonstrated the implication of the anterior cingulate cortex and posterior insula. However, few studies have explored the causal mechanisms underlying the interactions between ADHD and pain. The implication of inflammatory mechanisms has been suggested but the signalling pathways involved have not been explored. Methods: We investigated the roles of purinergic signalling, at the crossroad of pain and neuroinflammatory pathways, by using a transgenic mouse line that carries a total deletion of the P2X4 receptor. Results: We demonstrated that P2X4 deletion prevents hyperactivity in the mouse model of ADHD. In contrast, the absence of P2X4 lowered thermal pain thresholds in sham conditions and did not affect pain sensitization in ADHD-like conditions. We further analysed microglia reactivity and the expression of inflammatory markers in wild type and P2X4KO mice. Our results revealed that P2X4 deletion limits microglia reactivity but at the same time exerts proinflammatory effects in the anterior cingulate cortex and posterior insula. Conclusion: This dual role of P2X4 could be responsible for the differential effects noted on ADHD-like symptoms and pain sensitization and calls for further studies to investigate the therapeutic benefit of targeting the P2X4 receptor in ADHD patients.

The Central Noradrenergic System in Neurodevelopmental Disorders: Merging Experimental and Clinical Evidence

The aim of this article is to highlight the potential role of the locus-coeruleus-noradrenergic (LC-NA) system in neurodevelopmental disorders (NdDs). The LC is the main brain noradrenergic nucleus, key in the regulation of arousal, attention, and stress response, and its early maturation and sensitivity to perinatal damage make it an interesting target for translational research. Clinical data shows the involvement of the LC-NA system in several NdDs, suggesting a pathogenetic role in the development of such disorders. In this context, a new neuroimaging tool, LC Magnetic Resonance Imaging (MRI), has been developed to visualize the LC in vivo and assess its integrity, which could be a valuable tool for exploring morphological alterations in NdD in vivo in humans. New animal models may be used to test the contribution of the LC-NA system to the pathogenic pathways of NdD and to evaluate the efficacy of NA-targeting drugs. In this narrative review, we provide an overview of how the LC-NA system may represent a common pathophysiological and pathogenic mechanism in NdD and a reliable target for symptomatic and disease-modifying drugs. Further research is needed to fully understand the interplay between the LC-NA system and NdD.

The role of moment-to-moment dynamics of perceived stress and negative affect in co-occurring ADHD and internalising symptoms

A maladaptive response to stress in individuals with high ADHD traits may be a key factor explaining co-occurring ADHD symptoms and internalising problems. The current study investigates whether between-person differences in ADHD traits are associated with differences in the within-person moment-to-moment coupling of stress and negative affect; and whether these can explain between-person differences in internalising problems (N = 262, median-age 20). Results of a dynamic structural equation model indicated that between-person differences in ADHD traits significantly moderated the daily life coupling between stress and negative affect. Further, higher ADHD traits were associated with stronger stress carry-over and higher mean levels of negative affect. Stress carry-over and mean levels of negative affect mediated the association between ADHD traits and internalising problems.

The translational genetics of ADHD and related phenotypes in model organisms

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder resulting from the interaction between genetic and environmental risk factors. It is well known that ADHD co-occurs frequently with other psychiatric disorders due, in part, to shared genetics factors. Although many studies have contributed to delineate the genetic landscape of psychiatric disorders, their specific molecular underpinnings are still not fully understood. The use of animal models can help us to understand the role of specific genes and environmental stimuli-induced epigenetic modifications in the pathogenesis of ADHD and its comorbidities. The aim of this review is to provide an overview on the functional work performed in rodents, zebrafish and fruit fly and highlight the generated insights into the biology of ADHD, with a special focus on genetics and epigenetics. We also describe the behavioral tests that are available to study ADHD-relevant phenotypes and comorbid traits in these models. Furthermore, we have searched for new models to study ADHD and its comorbidities, which can be useful to test potential pharmacological treatments.

Adolescent chronic unpredictable stress leads to increased anxiety and attention deficit/hyperactivity-like symptoms in adulthood

BACKGROUND

Early-life adversities during development (e.g., child abuse and neglect) are linked to multiple behavioral and cognitive dysfunctions, such as attention deficit/hyperactivity disorder (ADHD) and anxiety disorders, which have high comorbidity. However, the impact of adversities during adolescence, a crucial period in early life for these disorders, is understudied. Using a chronic unpredictable stress (CUS) model in rats, we investigated whether adversities in adolescence could lead to increased anxiety and ADHD-like symptoms in adulthood.

METHODS

Mid- to late-adolescent (5-7-week-old) male and female Sprague-Dawley rats underwent a mild CUS procedure for 2 weeks. Various stressors were applied in an unpredictable way. Rats of both sexes were then trained with a 2-choice reaction time (2-CRT) task during adulthood, which are designed to detect ADHD-like symptoms, including increased impulsivity and lapse of attention. In addition, an open field test was conducted to examine if CUS resulted in a persistent increase in anxiety-like behavior during adulthood.

RESULTS

Both male and female rats with CUS exposure travelled shorter distances in the open field and spent less time in the center zone, indicating increased anxiety. In the 2-CRT task, rats of both sexes with CUS exposure showed increased impulsivity. Augmented lapses of attention were observed in female but not male rats.

CONCLUSION

Chronic unpredictable stress during adolescence increases anxiety and leads to ADHD-like symptoms in both male and female rats in adulthood. The deficits are more severe in females than in males. These observations support that adversities during adolescence persistently increase anxiety, which is comorbid with attention deficits.

Exploring the relationship between ADHD, its common comorbidities, and their relationship to organizational skills

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder affecting numerous executive functioning skills, such as organizational skills. While the relationship between the inattention aspect of ADHD and poor organizational skills is well documented, it is still unclear if lower organizational skills are only associated with ADHD or if they are also associated with other comorbid disorders commonly diagnosed in conjunction with ADHD. The purpose of the present study is to investigate the relationship between organizational skills and ADHD in adults, as well as the impact of comorbid disorders on ADHD in relation to organizational skills.

METHODS

Four hundred seven (n = 201 with a diagnosis of ADHD) adults from the general population were recruited online. Participants completed a measure of organizational skills, measures assessing levels of ADHD, depression, and anxiety, and extensive demographic information related to their diagnosis of ADHD or other possible diagnosis.

RESULTS

Participants with a diagnosis of ADHD were significantly more likely to have a comorbid diagnosis of depression and/or anxiety. Organizational skills were significantly lower in individuals who reported having received a diagnosis of ADHD, but not in those with a past diagnosis of depression and anxiety. However, organizational skills were lower in individuals currently experiencing higher levels of depression and anxiety. The results of regression analyses suggest that levels of organizational skills are most strongly predicted by inattention and more weakly predicted by comorbid disorders.

DISCUSSION

These results highlight the centrality of organizational skills deficit in ADHD as well as the influence of the inattention component over other components commonly observed in ADHD on organizational skills. Suggestions for treatment of ADHD in adults are discussed.

Dendritic and behavioral changes in rats neonatally treated with homocysteine; A proposal as an animal model to study the attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHAD) is a neurobehavioral disorder that affects children and adolescents with a high prevalence. Despite its prevalence and an unclear etiology, previous reports suggest that it is closely related to homocysteine metabolism. Male Sprague Dawley rats were administered with homocysteine from postnatal day (PD) 2 to PD 16. Locomotor activity was evaluated at 35 PD (prepuberal age) and 60 PD (adult age) before and after amphetamine administration. In rats evaluated at both ages, homocysteine induced hyperactivity, and the amphetamine administration reduced hyperactivity significantly at 35 PD, but not at 60 PD. In the social interaction test, homocysteine reduced the number of contacts and increased the latency to the first contact only in rats at 35 PD. Homocysteine also had an effect on short term memory at 35D and 60 PD and long-term memory at 60 PD. Morphological changes were found mainly in the shape of dendritic spines in the prefrontal cortex (PFC-3), dorsal hippocampus (CA1), dentate gyrus (DG) and nucleus accumbens (NAcc), in rats administered neonatally with homocysteine at both ages studied. In prepuberal and adult rats, there was an increase in dendritic length in DG and NAcc, respectively. The dendritic spine morphology also was altered at both ages, mainly decreasing the number of mushroom spines in NAcc and CA1 at 30 PD and in all the areas studied at 60 PD rats. Those areas are associated with the processes of attention, learning and memory that were studied, and those alterations are possibly related to changes observed in the behavioral tests. These behavioral and morphological changes in rats at 35 PD administered with homocysteine could be similar to changes found in children diagnosed with ADHD. Moreover, half to two thirds of children diagnosed with ADHD reach adulthood with this disorder. In this study we found similarities with ADHD, finding alterations in both rats at 35 PD and 60 PD. So, this may be proposed as an animal model to study this disorder present in children, adolescents and adults.

Self esteem and clinical features in a clinical sample of children with ADHD and social anxiety disorder

OBJECTIVE

In this study, we aimed to investigate self-esteem and clinical features in clinically referred children and adolescents with attention-deficit/hyperactivity disorder (ADHD) and comorbid Social Anxiety Disorder (SAD) and compare these to children and adolescents without SAD.

METHODS

One hundred and twenty child and adolescent drug-naïve outpatients (6-15 years of age) with a primary diagnosis of ADHD were included. Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version (K-SADS-PL), was used to evaluate ADHD and comorbidities. Parents filled in clinical and sociodemographic data form, Conners Parent Rating Scale (CPRS) and patients filled in Rosenberg Self-esteem Scale (RSES) and Çapa Social Phobia Scale for children and adolescents (ÇESFÖ).

RESULTS

Forty-six of the 120 (38.3%) children had comorbid SAD. Forty-six patients with SAD (ADHD + SAD group) and 74 patients without SAD (ADHD without SAD group) were compared in terms of the sociodemographic and clinical features, rate of psychiatric comorbidities, and rating scale scores. The rate of inattentive subtype of ADHD (p = 0.009), and social anxiety symptom scores (p < 0.001) were higher and self-esteem was lower (p < 0.001) in the ADHD + SAD group. Additionally, there was a statistically significant correlation between ÇESFÖ scores and CPRS anxiety subscale scores (r = 0.300, p = 0.001), and also Rosenberg self-esteem scale scores (r = 0.470, p < 0.001).

CONCLUSION

Children and adolescents with ADHD who had comorbid SAD may differ from ADHD patients without SAD in terms of ADHD subtype, clinical features and self-esteem.

Animal models of attention-deficit hyperactivity disorder (ADHD)

Attention-deficit hyperactivity disorder (ADHD) is a heterogeneous neuropsychiatric disorder characterized by three primary symptoms hyperactivity, attention deficit, and impulsiveness, observed in both children and adults. In childhood, this disorder is more common in boys than in girls, and at least 75% will continue to suffer from the disorder until adulthood. Individuals with ADHD generally have poor academic, occupational, and social functioning resulting from developmentally inappropriate levels of hyperactivity and impulsivity, as well as impaired ability to maintain attention on motivationally relevant tasks. Very few drugs available in clinical practice altogether abolish the symptoms of ADHD, therefore, to find new drugs and target it is essential to understand the neuropathological, neurochemical, and genetic alterations that lead to the progression of ADHD. With this contrast, an animal study is the best approach because animal models provide relatively fast invasive manipulation, rigorous hypothesis testing, as well as it provides a better angle to understand the pathological mechanisms involved in disease progression. Moreover, animal models, especially for ADHD, serve with good predictive validity would allow the assessment and development of new therapeutic interventions, with this aim, the present review collect the various animal models on a single platform so that the research can select an appropriate model to pursue his study.

An ecological momentary assessment study of the role of emotional dysregulation in co-occurring ADHD and internalising symptoms in adulthood

Previous ecological momentary assessment (EMA) research in children has suggested that emotional dysregulation problems are commonly associated with ADHD symptoms and may help explain their relatively strong co-occurrence with anxiety and depression (collectively referred to as 'internalising problems'); however, this has yet to be replicated for adults. In this study, we used data from a n=260 longitudinal cohort and EMA study, to evaluate the hypothesis that emotional dysregulation mediates the association between ADHD symptoms and internalising problems in emerging adulthood. Emotional dysregulation was based on affect data collected in near real time and in ecological context over a 14-day period, providing a measure of emotional lability in the context of participants' daily lives. Cross-sectional mediation was tested using structural equation modelling. Emotional lability significantly mediated the association between ADHD symptoms and internalising problems. Results suggest that interventions that address the emotional dysregulation aspects of ADHD are likely to be beneficial for preventing and managing secondary internalising symptoms.

Attention-deficit/hyperactivity disorder is characterized by a delay in subcortical maturation

Although previous studies have found that ADHD is characterized by a delay in cortical maturation, it is not clear whether this phenomenon was secondary to developmental trajectories in subcortical regions (caudate, putamen, pallidum, thalamus, hippocampus and amygdala). Using the ADHD-200 dataset, we estimated subcortical volumes in 339 individuals with ADHD and 568 typically developing controls. We defined the growth trajectory of each subcortical structure, delineating a phase of childhood increase followed by an adolescent decrease in subcortical volumes using a quadratic growth model. From these trajectories, the age of attaining peak subcortical volumes was derived and used as an index of subcortical maturation. We found that subcortical structures (caudate, putamen, pallidum, thalamus, hippocampus and amygdala) followed curvilinear trajectories similar to those reported in previous studies. The volumes of these subcortical structures in ADHD were also delayed in the developmental trajectory, which suggested that ADHD may be characterized by a delay in subcortical maturation. This delay may lead to a shift in which individuals with ADHD go through the process of pruning the nerve connections that is part of the normal maturation process during adolescence. Further, we also found that the asymmetric development of subcortical structures was abnormal in ADHD, which resulted from the imbalance of the maturation delay of bilateral subcortical structures. The subcortical maturation delay may play an important role in the pathophysiology of ADHD. Our findings provide new potential targets to investigate the pathophysiology of ADHD.

The Strengths and Difficulties Questionnaire Predicts Concurrent Mental Health Difficulties in a Transdiagnostic Sample of Struggling Learners

Children and adolescents with developmental problems are at increased risk of experiencing mental health problems. The Strengths and Difficulties Questionnaire (SDQ) is widely used as a screener for detecting mental health difficulties in these populations, but its use thus far has been restricted to groups of children with diagnosed disorders (e.g., ADHD). Transdiagnostic approaches, which focus on symptoms and soften or remove the boundaries between traditional categorical disorders, are increasingly adopted in research and practice. The aim of this study was to assess the potential of the SDQ to detect concurrent mental health problems in a transdiagnostic sample of children. The sample were referred by health and educational professionals for difficulties related to learning (N = 389). Some had one diagnosis, others had multiple, but many had no diagnoses. Parent-rated SDQ scores were significantly positively correlated with parent ratings of mental health difficulties on the Revised Child Anxiety and Depression Scale (RCADS). Ratings on the SDQ Emotion subscale significantly predicted the likelihood of having concurrent clinical anxiety and depression scores. Ratings on the Hyperactivity subscale predicted concurrent anxiety levels. These findings suggest the SDQ could be a valuable screening tool for identifying existing mental health difficulties in children recognized as struggling, as it can be in typically developing children and those with specific diagnoses.

Association of ADHD symptoms, depression and suicidal behaviors with anxiety in Chinese medical college students

BACKGROUND

Anxiety is one of the most common psychiatric disorder and imposes a great burden on both the individual and the society. Previous studies indicate a high comorbidity of anxiety disorders and Attention Deficit Hyperactivity Disorder (ADHD). However, few studies have examined the comorbidity of anxiety and ADHD among medical college students in mainland China. This study aimed to examine the prevalence of anxiety and the associated risk factor of anxiety disorder as well as to explore the association between ADHD symptoms, depression, suicidal behaviors and anxiety.

METHODS

A cross-sectional design was employed among 4882 medical college students who were recruited and enrolled with convenience sampling. Self-reported demographic information and clinical characteristics were collected online on a computer or through a social media app named Wechat.

RESULTS

The prevalence of anxiety in this study was 19.9%. Students with anxiety were more likely to have a poor relationship with parents, be of Han nationality, have smoking or drinking habits, have an extensive physical disorder history and have engaged in suicidal behaviors. The independent risk factors for anxiety were: smoking, physical disorder history, suicidal ideations, suicide attempts, inattention and hyperactivity. Significant associations were observed between anxiety and depression, inattention, hyperactivity, suicide plans and suicide attempts.

CONCLUSIONS

Nearly one in five medical students suffered from anxiety. The findings of this study indicate the importance of addressing both anxiety and ADHD symptoms in order to better promote mental health and the well-being of medical students as well as reduce suicidal behaviors.

Comorbidity between ADHD and anxiety disorders across the lifespan

Objectives: Attention deficit/hyperactivity disorder (ADHD) and anxiety disorders are among the most common psychiatric disorders with a 25% comorbidity rate with each other. In this study, we overview the comorbidity between ADHD and anxiety disorders in a longitudinal perspective across the lifespan and we discuss possible therapeutic strategies.Methods: A literature search was performed using PubMed to identify clinical studies assessing comorbidity between ADHD and anxiety disorders from childhood to adulthood.Results: Anxiety disorders may substantially change the presentation, the prognosis, and the treatment of ADHD itself. In childhood, the presence of generalised anxiety disorder, could prevent the typical inhibitory dysfunction present in ADHD, in adolescence may increase the deficit of working memory, and in adulthood may enhance the presence of sleep problems. Individuals with comorbid ADHD and anxiety disorders would benefit from adjunctive psychosocial or adjunctive pharmacotherapy interventions to cognitive behavioural treatment.Conclusions: The management of individuals with comorbid ADHD and anxiety disorders could be challenging for clinicians, and assessing the developmental course is crucial in order to shed light on individualised treatment.KeypointsThe comorbidity between ADHD and anxiety disorders changes the clinical presentation, the prognosis and treatment of patients with ADHD across lifespan.ADHD and anxiety disorders shared common neurobiological dysfunctions but have also different neurobiological abnormalities suggesting that they are different diagnoses.These patients are less likely to benefit from cognitive behavioural treatment strategies alone and often need adjunctive pharmacological treatments.Studies that evaluated the response to MPH reported conflicting results. These patients could respond less well and get more unpleasant arousal side-effects, but these findings need to be confirmed.For his unique mechanism of action, low dose aripiprazole treatment in adolescents and adults with this comorbid condition could be an intriguing avenue of exploration.

Attention deficit hyperactivity disorder and comorbidity: A review of literature

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with onset in early childhood. It is a clinically heterogenous condition with comorbidity posing a distinct challenge to diagnosing and managing these children and adolescents. This review aims to provide an overview of comorbidity with ADHD including other neurodevelopmental disorders, learning disorders, externalising and internalising disorders. Challenges in screening for, diagnosing and managing comorbidity with ADHD are summarised. Also, methodological challenges and future directions in research in this interesting field are highlighted.

Sensory Over-Responsivity as an Added Dimension in ADHD

Years of research have added to our understanding of Attention Deficit Hyperactivity Disorder (ADHD). None-the-less there is still much that is poorly understood. There is a need for, and ongoing interest in, developing a deeper understanding of this disorder to optimally identify risk and better inform treatment. Here, we present a compilation of findings examining ADHD both behaviorally and using neurophysiologic markers. Drawing on early work of McIntosh and co-investigators, we examined response to sensory challenge in children with ADHD, measuring HPA activity and electrodermal response (EDR) secondary to sensory stressors. In addition, we have examined the relationship between these physiologic measures, and reports of behavioral sensory over-responsivity and anxiety. Findings suggest that sensory responsivity differentiates among children with ADHD and warrants consideration. We link these findings with research conducted both prior to and after our own work and emphasize that there a growing knowledge supporting a relationship between ADHD and sensory over-responsivity, but more research is needed. Given the call from the National Institute of Health to move toward a more dimensional diagnostic process for mental health concerns, and away from the more routine categorical diagnostic process, we suggest sensory over-responsivity as a dimension in the diagnostic process for children with ADHD.

Does Anxiety Modify the Risk for, or Severity of, Conduct Problems Among Children With Co-Occurring ADHD: Categorical and Dimensional and Analyses

OBJECTIVE

The goal was to examine whether anxiety modifies the risk for, or severity of, conduct problems in children with ADHD.

METHOD

Assessment included both categorical and dimensional measures of ADHD, anxiety, and conduct problems. Analyses compared conduct problems between children with ADHD features alone versus children with co-occurring ADHD and anxiety features.

RESULTS

When assessed by dimensional rating scales, results showed that compared with children with ADHD alone, those children with ADHD co-occurring with anxiety are at risk for more intense conduct problems. When assessment included a Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) diagnosis via the Schedule for Affective Disorders and Schizophrenia for School Age Children-Epidemiologic Version (K-SADS), results showed that compared with children with ADHD alone, those children with ADHD co-occurring with anxiety neither had more intense conduct problems nor were they more likely to be diagnosed with oppositional defiant disorder or conduct disorder.

CONCLUSION

Different methodological measures of ADHD, anxiety, and conduct problem features influenced the outcome of the analyses.

An examination of the association between anxiety and social functioning in youth with ADHD: A systematic review

Although up to 50% of children with Attention-Deficit/Hyperactivity Disorder (ADHD) meet criteria for an anxiety disorder, it is unclear how comorbid anxiety influences social functioning for this population. Understanding the factors associated with social functioning in ADHD is important given the limited efficacy of existing social skills interventions for this population. This systematic review aimed to determine the association between anxiety and social functioning (social problems, peer status, and social skills/ competence) in children and adolescents with ADHD. A standardised search protocol was used, identifying 4807 articles for screening with 31 included in the final review. Anxiety symptom severity was associated with lower levels of social skills and higher levels of social problems in young people with ADHD. However, few differences emerged when defining anxiety based on diagnostic measures. Although the results varied considerably amongst studies, a number of key variables emerged that influenced the associations between anxiety and social functioning including the type of reporter and sample characteristics such as age, sex, ADHD subtype and other mental health comorbidities. These findings have implications for social functioning interventions in ADHD given the role of anxiety symptoms in predicting poorer social functioning.

Disrupted reinforcement learning during post-error slowing in ADHD

ADHD is associated with altered dopamine regulated reinforcement learning on prediction errors. Despite evidence of categorically altered error processing in ADHD, neuroimaging advances have largely investigated models of normal reinforcement learning in greater detail. Further, although reinforcement leaning critically relies on ventral striatum exerting error magnitude related thresholding influences on substantia nigra (SN) and dorsal striatum, these thresholding influences have never been identified with neuroimaging. To identify such thresholding influences, we propose that error magnitude related activities must first be separated from opposite activities in overlapping neural regions during error detection. Here we separate error detection from magnitude related adjustment (post-error slowing) during inhibition errors in the stop signal task in typically developing (TD) and ADHD adolescents using fMRI. In TD, we predicted that: 1) deactivation of dorsal striatum on error detection interrupts ongoing processing, and should be proportional to right frontoparietal response phase activity that has been observed in the SST; 2) deactivation of ventral striatum on post-error slowing exerts thresholding influences on, and should be proportional to activity in dorsal striatum. In ADHD, we predicted that ventral striatum would instead correlate with heightened amygdala responses to errors. We found deactivation of dorsal striatum on error detection correlated with response-phase activity in both groups. In TD, post-error slowing deactivation of ventral striatum correlated with activation of dorsal striatum. In ADHD, ventral striatum correlated with heightened amygdala activity. Further, heightened activities in locus coeruleus (norepinephrine), raphe nucleus (serotonin) and medial septal nuclei (acetylcholine), which all compete for control of DA, and are altered in ADHD, exhibited altered correlations with SN. All correlations in TD were replicated in healthy adults. Results in TD are consistent with dopamine regulated reinforcement learning on post-error slowing. In ADHD, results are consistent with heightened activities in the amygdala and non-dopaminergic neurotransmitter nuclei preventing reinforcement learning.

Association Between Altitude and Regional Variation of ADHD in Youth

OBJECTIVE

The purpose of this study was to evaluate the effect of altitude on rates of ADHD. As decreased dopamine (DA) activity has been reported with ADHD and hypoxia has shown to be associated with increased DA, we hypothesized that states at higher altitudes would have lower rates of ADHD.

METHOD

State estimates from the 2007 National Survey of Children's Health (NSCH) report and 2010 National Survey of Children with Special Health Care Needs (NS-CSHCN) report were used to extract the percentages of youth ages 4 to 17 diagnosed with ADHD.

RESULTS

Both the datasets independently revealed that the prevalence of ADHD decreases with increasing altitude ( R2 = .38, p < .001; R2 = .31, p < .001), respectively. This study controlled for potential confounds (e.g., low birth weight, ethnicity, and household size).

CONCLUSION

These findings suggest a need for further investigation into the extent by which altitude may serve as a protective factor for ADHD.

Estimated prevalence and associated risk factors of attention deficit hyperactivity disorder (ADHD) among medical college students in a Chinese population

BACKGROUND

To investigate the prevalence of attention deficit hyperactivity disorder (ADHD) among medical college students in a Chinese population.

METHODS

A cross-sectional design was used to collect demographic data on participants and their symptoms of ADHD, anxiety, and depression. Data were collected through questionnaires filled out on a computer or through WeChat, a widely used social media app.

RESULTS

The prevalence of ADHD among 5693 college students was 3.5% (3.02∼3.98%). Individuals with ADHD showed higher scores on scales of anxiety and depression symptoms (both p < 0.05) than the general population. There was a significant difference in the prevalence of ADHD grouped by smoking, drinking, suicidal ideation, suicidal plans, suicidal attempt, anxiety and depression (p < 0.05). The odds ratio (OR) of ADHD was high for suicidal ideation, suicide plans, suicide attempts, anxiety and depression, with ORs of 5.901, 5.46, 6.011, 8.037 and 7.88, respectively. The ORs of suicidal behaviors for ADHD were decreased after adjusting for covariates such as drinking, smoking and depression.

LIMITATIONS

The sample was exclusively selected from three medical-related colleges, which might not be best representation of college students in China. Furthermore, majority of the participants were females.

CONCLUSIONS

ADHD remains a common disorder among Chinese medical college students and is significantly associated with suicidal behaviors, anxiety and depression. It is important to increase awareness and promote effective interventions to this particular population.

Anxiety modulates the relation between attention-deficit/hyperactivity disorder severity and working memory-related brain activity

OBJECTIVES

Individuals with attention-deficit/hyperactivity disorder (ADHD) often have heightened levels of anxiety, which has been associated with worse performance on working memory tasks. Knowledge of the neural pathways underlying the combined presence of ADHD and anxiety may aid in a better understanding of their co-occurrence. Therefore, we investigated how anxiety modulates the effect of ADHD severity on neural activity during a visuospatial working memory (VSWM) task.

METHODS

Neuroimaging data were available for 371 adolescents and young adults participating in the multicentre cohort study NeuroIMAGE (average age 17.1 years). We analysed the effects of ADHD severity, anxiety severity and their interaction on-task accuracy, and on neural activity associated with working memory (VSWM trials minus baseline), and memory load (high memory load trials minus low load trials).

RESULTS

Anxiety significantly modulated the relation between ADHD severity and neural activity in the cerebellum for the working memory contrast, and bilaterally in the striatum and thalamus for the memory load contrast.

CONCLUSIONS

We found that ADHD with co-occurring anxiety is associated with lowered neural activity during a VSWM task in regions important for information gating. This fits well with previous theorising on ADHD with co-occurring anxiety, and illustrates the neurobiological heterogeneity of ADHD.

Correlates of Anxiety in 6- to 8-Year-Old Children With ADHD: A Community-Based Study

OBJECTIVE

The aim of this study was to identify the child and parent/family correlates of anxiety in a community-based sample of children with ADHD.

METHOD

Children (6-8 years) with ADHD ( n = 179) and controls ( n = 212) were assessed for ADHD and anxiety using the Diagnostic Interview Schedule for Children IV. Potential child and parent/family correlates were measured through direct assessments, and parent- and teacher-reported questionnaires. Associations were examined using univariate and multivariate logistic regression analyses.

RESULTS

One in four children with ADHD ( n = 44) met criteria for an anxiety disorder, compared with one in 20 controls ( n = 10). Anxiety was common in both boys and girls with ADHD. The strongest correlates of anxiety in multivariate analyses were ADHD subtype, primary caregiver psychosocial distress, and neighborhood socioeconomic disadvantage.

CONCLUSION

Anxiety is common in children with ADHD. This study provides insight into the potential parent/family stressors that may increase risk for anxiety in children with ADHD.

Dopaminergic innervation and modulation of hippocampal networks

The catecholamine dopamine plays an important role in hippocampus-dependent plasticity and related learning and memory processes. Dopamine secretion in the hippocampus is activated by, e.g., salient or novel stimuli, thereby helping to establish and to stabilize hippocampus-dependent memories. Disturbed dopaminergic function in the hippocampus leads to severe pathophysiological conditions. While the role and importance of dopaminergic modulation of hippocampal networks have been unequivocally proven, there is still a lack of detailed molecular and cellular mechanistic understanding of how dopamine orchestrates these hippocampal processes. In this chapter of the special issue "Hippocampal structure and function," we will discuss the current understanding of dopaminergic modulation of basal synaptic transmission and long-lasting, activity-dependent potentiation or depression.

Obsessive-compulsive adults with and without childhood ADHD symptoms

Obsessive-compulsive disorder (OCD) and attention-deficit and hyperactivity disorder (ADHD) frequently coexist. To understand whether childhood ADHD can increase the risk of OCD in adulthood and whether it influences the phenomenology of OCD, we investigated the symptoms of ADHD during childhood in obsessive-compulsive adults who had never been diagnosed as ADHD. Adults with OCD (n = 83) were given the Wender Utah Rating Scale (WURS), Yale-Brown Obsessive Compulsive Scale (Y-BOCS), Barratt Impulsiveness Scale-11 (BIS-11), Hamilton Depression Rating Scale-17 (HDRS-17) and Beck Anxiety Inventory (BAI). The prevalence of childhood ADHD symptoms was 40.9 % (n = 34) and that of adult ADHD was 16.9 % (n = 14). Patients with childhood ADHD symptoms had an earlier onset of OCD, higher scores of the BAI and BIS-11. The scores of the Y-BOCS and HDRS-17 did not differ between those having and not having childhood ADHD symptoms. Childhood history of ADHD symptoms is common in adult OCD patients who have never been diagnosed as ADHD. Childhood ADHD symptoms are associated with an earlier age of OCD, more severe anxiety and higher impulsiveness. Even remitted ADHD may be a risk factor for OCD in later life.

Atomoxetine treatment in adults with attention-deficit/hyperactivity disorder

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a CNS disorder that has its onset in childhood, but often persists into adulthood. There is growing recognition that adult ADHD can result in multiple negative consequences for individuals. ADHD is also often associated with a number of comorbid psychiatric disorders. Atomoxetine (ATX), a nonstimulant, selective noradrenergic reuptake inhibitor, was approved in the United States in 2002 for the treatment of ADHD in children and adolescents, as well as adults. We review here the safety and efficacy of ATX in adults with ADHD, including data in special populations, functional outcomes, as well as provider and patient real-world perceptions.

METHODS

We searched the databases Embase, MEDLINE and PsycINFO using the terms 'ADHD' and 'adult' and 'ATX' capturing publications from January 1, 1998, to March 27, 2014. Only publications in English were considered.

RESULTS

ATX demonstrated significantly greater improvement than placebo (PBO) on the Conners Adult ADHD Rating Scale-Investigator rated:Screening Version (CAARS-Inv:SV) in all trials (N = 6; total score difference ranged from -3.5 to -5.5). For long-term trials using the CAARS-Inv:SV, ATX demonstrated significantly greater improvement than PBO in three of four trials (total score differences ranged from -0.1 to -6.0). In short-term studies, ATX showed significantly greater improvement than PBO on the Adult ADHD Quality-of-Life scale total score in three of three studies, but results were mixed on the Sheehan Disability Scale. Three studies of ATX have reported statistically significant improvement (compared with PBO) on the Behavior Rating Inventory of Executive Function-Adult Version Self Report scale. The most common adverse events (occurring in ≥ 10% of patients taking ATX) were nausea, dry mouth, decreased appetite, insomnia and fatigue.

CONCLUSIONS

ATX is an important treatment option for the right patient. ATX can provide long-term, consistent symptom relief and functional improvement for adults with ADHD.

Anxiety Disorders Comorbidity in Children and Adolescents with Attention Deficit Hyperactivity Disorder

INTRODUCTION

Our aim is to investigate the prevalence of comorbidity of anxiety disorders (AD) among patients newly diagnosed with attention deficit hyperactivity disorder (ADHD) and to compare symptom severity of ADHD and sociodemographic parameters between patients with and without AD.

METHODS

Among 1683 children and adolescents admitted to Kocaeli University Medical Faculty, Child and Adolescent Mental Health Outpatient Clinic, 447 children and adolescents, who were preliminarily diagnosed as ADHD by clinical interview based on Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), were invited to participate in the second phase of the study. Kiddie Schedule for Affective Disorder and Schizophrenia, Present and Lifetime-Turkish Version were applied to children and adolescents with ADHD and one of their parents to support the diagnoses of both ADHD and AD. Mothers, fathers, and teachers of the children were asked to complete DSM-IV-Based Child and Adolescent Behavior Disorders Screening and Rating Scale.

RESULTS

Our study group comprised 170 children and adolescents diagnosed with ADHD of whom 19.4% were girls and 80.6% were boys; 27.6% of patients diagnosed with ADHD showed AD comorbidity. Age of the parents at birth of the patients with AD was significantly lower than that of patients without AD.

CONCLUSION

In line with the previous studies, the comorbidity rate of AD was found to be higher among patients with ADHD than general population and clinical sample without ADHD. The possibility of comorbidity of AD in patients with ADHD should be considered because higher rates of AD are observed in ADHD and comorbidities of AD.

Dual ameliorative effects of Ningdong granule on dopamine in rat models of Tourette's syndrome

Dopamine (DA) is a key neuromodulator in the brain that supports motor and cognitive functions. Here, we use apomorphine (Apo) and 3,3'-iminodipropionitrile (IDPN) to develop two rat models of Tourette's syndrome (TS), a common neuropsychiatric disorder characterized by stereotyped repetitive involuntary tics. The models enabled the assessment of unique ameliorative effects of Ningdong granule (NDG), a traditional Chinese medicine (TCM) preparation dedicated to the treatment of TS, on the striatal DA content of rats. By using high-performance liquid chromatography (HPLC), we found that long-term administration of NDG could, at least partially, restore the striatal dopamine alterations, either by increasing them after IDPN treatment or by decreasing them after Apo treatment. Taken together, our data indicated that NDG could ameliorate the abnormal striatal DA content dually, and the unique therapeutic property may be meaningful for the treatment of TS.

The Amygdala's Neurochemical Ratios after 12 Weeks Administration of 20 mg Long-acting Methylphenidate in Children with Attention Deficit and Hyperactivity Disorder: A Pilot Study Using (1)H Magnetic Resonance Spectroscopy

Objective

Recent pediatric studies have suggested a correlation between decreased amygdala volume and attention deficit and hyperactivity disorder (ADHD) symptoms, including the emotional dysregulation. To investigate the hypothesis that medication treatment of ADHD specifically improves amygdala function, we used ¹H magnetic resonance spectroscopy (MRS) to study the effect of 12 weeks of treatment with daily 20 mg long-acting methylphenidate on the Glu/Cr, NAA/Cr, Cho/Cr, and mI/Cr ratios in the amygdala of medication-naïve children with ADHD.

Methods

This was a prospective study, using a pre- and post-test design, on a single group of 21 children (average age 8.52 years, 17 males and 4 females) diagnosed with ADHD. Low Time Echo MRS scans sampled voxels of interest (1.5×1.5×2.0) from both the right and left amygdala.

Results

There was significant clinical improvement after 12 weeks of treatment with 20 mg long-acting methylphenidate. On 1H MRS, there were no statistical significant differences of NAA/Cr ratio, Cho/Cr ratio, mI/Cr ratio before and after 12 weeks administration of 20 mg long-acting methylphenidate both in the right and left amygdala. In addition, Glu/Cr ratio decreased 14.1% in the right amygdala (p=0.029) and 11.4% in the left amygdala (p=0.008). Standardized mean effect sizes ranged from 0.14-0.32.

Conclusion

The findings are consistent with the possibility that hyperglutamatergic processes in the amygdale are related to the hyperactive-impulsive symptoms of ADHD.

Stimulant treatment of ADHD and cigarette smoking: a meta-analysis

BACKGROUND AND OBJECTIVE

Individuals with attention-deficit/hyperactivity disorder (ADHD) have a significantly higher risk of cigarette smoking. The nature of the relationship between smoking and psychostimulant medications commonly used to treat ADHD is controversial. Our objective was to examine the relationship between stimulant treatment of ADHD and cigarette smoking by using meta-analysis, and to identify study and sample characteristics that moderate this relationship.

METHODS

Literature searches on PubMed and PsycInfo databases identified published studies for inclusion. Included studies compared cigarette smoking outcomes for stimulant-treated and untreated ADHD individuals. Seventeen studies met inclusion criteria, and 14 (total n = 2360) contained sufficient statistical information for inclusion in the meta-analysis. Two authors extracted odds ratios or frequencies of smokers in the treatment or nontreatment groups, and coded study characteristics including sample source, percentage of male participants, follow-up length, treatment consistency, type of smoking measure, prospective study, and controlling for comorbidities.

RESULTS

Meta-analysis revealed a significant association between stimulant treatment and lower smoking rates. Meta-regression indicated that effect sizes were larger for studies that used clinical samples, included more women, measured smoking in adolescence rather than adulthood, conceptualized stimulant treatment as consistent over time, and accounted for comorbid conduct disorder.

CONCLUSIONS

Nearly all studies were naturalistic, precluding causal inferences. Available data were insufficient to examine additional influences of patient demographics, treatment effectiveness, or other comorbidities. Consistent stimulant treatment of ADHD may reduce smoking risk; the effect was larger in samples with more severe psychopathology. Implications for further research, treatment of ADHD, and smoking prevention are discussed.

Prefrontal grey and white matter neurometabolite changes after atomoxetine and methylphenidate in children with attention deficit/hyperactivity disorder: a (1)H magnetic resonance spectroscopy study

Attention deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral childhood disorder. Dysfunction of prefrontal neural circuits which are responsible for executive and attentional functions has been previously shown in ADHD. We investigated the neurometablite changes in areas included in dorsolateral prefrontal neural circuits after 2 months of long-acting methylphenidate or atomoxetine medication in children with ADHD who were responders to treatment. Twenty-one ADHD children were examined by single voxel (1)H-magnetic resonance spectroscopy (MRS) before and after 2 months of medication with OROS methylphenidate (n=10) or atomoxetine (n=11). The spectra were taken from the dorsolateral prefrontal cortex (DLPFC, 8ml) and white matter behind the DLPFC (anterior semioval center, 7.5ml), bilaterally. NAA and NAA/Cr (N-acetylaspartate/creatine) decreased in the left DLPFC and Cho/Cr (choline/creatine) increased in the right DLPFC after atomoxetine medication. Glu+Gln and Glu+Gln/Cr (glutamate/glutamine) increased in the left white matter after methylphenidate medication. We hypothesize that atomoxetine could decrease hyperactivation of DLPFC neurons and methylphenidate could lead to increased activation of cortical glutamatergic projections with the consequences of increased tonic dopamine release in the mesocortical system.

Childhood and current ADHD symptom dimensions are associated with more severe cannabis outcomes in college students

BACKGROUND

Numerous studies have shown that attention deficit/hyperactivity disorder (ADHD) is associated higher risk of cannabis use disorders (CUD). However, these studies are limited in that most did not: (a) differentiate the role of hyperactivity-impulsivity (HI) and inattention (IN); (b) control for associated psychopathology; and (c) consider more fine-grained CUD-related measures. Our aim was to clarify the unique and interactive contributions of inattention and hyperactivity symptoms to age of cannabis initiation and DSM-IV cannabis dependence, craving, and severity of problems related to cannabis use while statistically controlling for symptoms of comorbid psychopathology in a non-clinical sample of young adults.

METHODS

Cannabis variables, current use of cigarettes and alcohol, current and childhood ADHD, and comorbid internalizing and externalizing psychopathology were assessed in 376 male and female undergraduates.

RESULTS

Results indicate that current and childhood IN were independently associated with more severe cannabis use, craving, and problem use-related outcomes in young adulthood (p's<.01) and that childhood HI symptoms were associated with earlier initiation of cannabis (p<.01). Further, current IN symptoms moderated the relationships between level of use and more severe outcomes (p's<.01), such that higher IN strengthened positive associations among use and problem cannabis use. Associations with ADHD symptom dimensions and current use of alcohol and cigarettes were also present.

CONCLUSIONS

Thus, current and childhood inattention symptoms as well as childhood hyperactive-impulsive symptoms emerged as significant factors in cannabis-related outcomes in young adults, even after statistically controlling for important confounding variables.

When attention-deficit/hyperactivity disorder co-occurs with anxiety disorders: effects on treatment

Anxiety disorders (ANX) and attention-deficit/hyperactivity disorder (ADHD) commonly co-occur; this comorbidity is associated with a high degree of impairment and a poor long-term prognosis. In this review, the nature of this comorbidity and its treatment will be described, and an approach to treating children with ANX + ADHD will be presented. The etiology of ANX + ADHD is controversial, with biological, developmental, environmental and cognitive factors examined in various studies. There is increasing evidence that ANX + ADHD may be distinct from each separate disorder, and may represent a neuropsychiatric condition that involves dysregulation in both anxiety and ADHD domains. Treatment usually requires a combination of medication and psychotherapeutic intervention. Stimulant medications have been found most helpful so far compared with other medications, although atomoxetine is also being studied. There is limited evidence for selective serotonin reuptake inhibitors, and their potential for behavioral activation may be problematic in these children. Intensive behavior modification was shown to be beneficial in conjunction with medication for ANX + ADHD in a multimodal treatment study of children with ADHD. Cognitive-behavioral therapy has been used to address anxiety symptoms, but may need to be individualized in ANX + ADHD as cognitive limitations and ADHD behaviors may otherwise interfere. Parental anxious or ADHD traits and the child's developmental level must also be considered to optimize treatment.

Origins of specificity during tDCS: anatomical, activity-selective, and input-bias mechanisms

Transcranial Direct Current Stimulation (tDCS) is investigated for a broad range of neuropsychiatric indications, various rehabilitation applications, and to modulate cognitive performance in diverse tasks. Specificity of tDCS refers broadly to the ability of tDCS to produce precise, as opposed to diffuse, changes in brain function. Practically, specificity of tDCS implies application-specific customization of protocols to maximize desired outcomes and minimize undesired effects. Especially given the simplicity of tDCS and the complexity of brain function, understanding the mechanisms leading to specificity is fundamental to the rational advancement of tDCS. We define the origins of specificity based on anatomical and functional factors. Anatomical specificity derives from guiding current to targeted brain structures. Functional specificity may derive from either activity-selectivity, where active neuronal networks are preferentially modulated by tDCS, or input-selectivity, where bias is applied to different synaptic inputs. Rational advancement of tDCS may require leveraging all forms of specificity.

Childhood trajectories of inattention, hyperactivity and oppositional behaviors and prediction of substance abuse/dependence: a 15-year longitudinal population-based study

Numerous prospective studies have shown that children diagnosed with attention deficit/hyperactivity disorder (ADHD) are at higher risk of long-term substance abuse/dependence. However, there are three important limits to these studies: (a) most did not differentiate the role of hyperactivity and inattention; (b) most did not control for associated behavioral problems; and (c) most did not consider females. Our aim was to clarify the unique and interactive contributions of childhood inattention and hyperactivity symptoms to early adulthood substance abuse/dependence. Behavioral problems of 1803 participants (814 males) in a population-based longitudinal study were assessed yearly between 6 and 12 years by mothers and teachers. The prevalence of substance abuse/dependence at age 21 years was 30.7% for nicotine, 13.4% for alcohol, 9.1% for cannabis and 2.0% for cocaine. The significant predictors of nicotine dependence were inattention (odds ratio (OR): 2.25; 95% confidence interval (CI): 1.63-3.11) and opposition (OR: 1.65; 95%: 1.20-2.28). Only opposition contributed to the prediction of cannabis dependence (OR: 2.33; 95% CI: 1.40-3.87) and cocaine dependence (OR: 2.97; 95% CI: 1.06-8.57). The best behavioral predictor of alcohol abuse/dependence (opposition) was only marginally significant (OR: 1.38; 95% CI: 0.98-1.95). Frequent oppositional behaviors during elementary school were clearly the most pervasive predictors of substance abuse/dependence in early adulthood. The association of childhood ADHD with substance abuse/dependence is largely attributable to its association with opposition problems during childhood. However, inattention remained an important predictor of nicotine dependence, in line with genetic and molecular commonalities between the two phenotypes suggested in the literature.

Sleep promotes consolidation of emotional memory in healthy children but not in children with attention-deficit hyperactivity disorder

Fronto-limbic brain activity during sleep is believed to support the consolidation of emotional memories in healthy adults. Attention deficit-hyperactivity disorder (ADHD) is accompanied by emotional deficits coincidently caused by dysfunctional interplay of fronto-limbic circuits. This study aimed to examine the role of sleep in the consolidation of emotional memory in ADHD in the context of healthy development. 16 children with ADHD, 16 healthy children, and 20 healthy adults participated in this study. Participants completed an emotional picture recognition paradigm in sleep and wake control conditions. Each condition had an immediate (baseline) and delayed (target) retrieval session. The emotional memory bias was baseline–corrected, and groups were compared in terms of sleep-dependent memory consolidation (sleep vs. wake). We observed an increased sleep-dependent emotional memory bias in healthy children compared to children with ADHD and healthy adults. Frontal oscillatory EEG activity (slow oscillations, theta) during sleep correlated negatively with emotional memory performance in children with ADHD. When combining data of healthy children and adults, correlation coefficients were positive and differed from those in children with ADHD. Since children displayed a higher frontal EEG activity than adults these data indicate a decline in sleep-related consolidation of emotional memory in healthy development. In addition, it is suggested that deficits in sleep-related selection between emotional and non-emotional memories in ADHD exacerbate emotional problems during daytime as they are often reported in ADHD.

Estimation of utilities in attention-deficit hyperactivity disorder for economic evaluations

BACKGROUND

Attempts to estimate the cost effectiveness of attention-deficit hyperactivity disorder (ADHD) treatments in the past have relied on classifying ADHD patients as responders or non-responders to treatment. Responder status has been associated with a small gain in health-related quality of life (HR-QOL) [or utility, as measured using the generic QOL measure EQ-5D] of 0.06 (on a scale from 0 being dead to 1.0 being full health).

OBJECTIVES

The goal of the present study was to develop and validate several ADHD-related health states, and to estimate utility values measured amongst the general public for those states and to re-estimate utility values associated with responder status.

METHODS

Detailed qualitative interview data were collected from 20 young ADHD patients to characterize their HR-QOL. In addition, item-by-item clinical and HR-QOL data from a clinical trial were used to define and describe four health states (normal; borderline to mildly ill; moderately to markedly ill; and severely ill). ADHD experts assessed the content validity of the descriptions. The states were rated by 100 members of the UK general public using the time trade-off (TTO) interview and visual analog scale. Statistical mapping was also undertaken to estimate Clinical Global Impression-Improvement (CGI-I) utilities (i.e. response status) from Clinical Global Impression-Severity (CGI-S) defined states. The mapping work estimated changes in utilities from study baseline to last visit for patients with a CGI-I score of ≤ 2 or ≤ 3.

RESULTS

The validity of the four health states developed in this study was supported by in-depth interviews with ADHD experts and patients, and clinical trial data. TTO-derived utilities for the four health states ranged from 0.839 (CGI-S state 'normal') to 0.444 (CGI-S state 'severely ill'). From the mapping work, the change in utility for treatment responders was 0.19 for patients with a CGI-I score of ≤ 2 and 0.15 for patients with a CGI-I score of ≤ 3.

CONCLUSIONS

The present study provides utilities for different severity levels of ADHD estimated in a TTO study. This approach provides a more granular assessment of the impact of ADHD on HR-QOL than binary approaches employed in previous economic analyses. Change in utility for responders and non-responders at different levels of CGI-I was estimated, and thus these utilities may be used to compare health gains of different ADHD interventions.

Child and caregiver issues in the treatment of attention deficit–hyperactivity disorder: education, adherence and treatment choice

There is much more to successful drug treatment than writing a prescription. In this article, we describe some of the ‘holistic’ aspects of the pharmacological treatment of attention deficit–hyperactivity disorder, with an emphasis on helping families to decide between psychological and pharmacological treatment and on the process of psychoeducation. Detailed accounts of drug and behavioral treatment in various circumstances are available elsewhere; however, the value and process of psychoeducation is sometimes underestimated or referred to in a cursory statement of the need for a good doctor–patient relationship. There has been little in the way of controlled trials, so no meta-analysis is attempted. Where possible (e.g., in reviewing the effects of psychological therapy and prediction of drug response), PubMed/Medline was searched for systematic reviews and randomized trials, but this article’s conclusions should be taken as personal. These subjective views are based chiefly on experience in clinical practice, participation in focus groups with young people and their families and work with support groups.

Prospective association of childhood attention-deficit/hyperactivity disorder (ADHD) and substance use and abuse/dependence: a meta-analytic review

Given the clinical and public health significance of substance disorders and the need to identify their early risk factors, we examined the association of childhood attention-deficit/hyperactivity disorder (ADHD) with substance use (nicotine, alcohol, marijuana) and abuse/dependence outcomes (nicotine, alcohol, marijuana, cocaine, other). To strengthen a potential causal inference, we meta-analyzed longitudinal studies that prospectively followed children with and without ADHD into adolescence or adulthood. Children with ADHD were significantly more likely to have ever used nicotine and other substances, but not alcohol. Children with ADHD were also more likely to develop disorders of abuse/dependence for nicotine, alcohol, marijuana, cocaine, and other substances (i.e., unspecified). Sex, age, race, publication year, sample source, and version of the Diagnostic and Statistical Manual of Mental Disorders (DSM) used to diagnose ADHD did not significantly moderate the associations with substance outcomes that yielded heterogeneous effect sizes. These findings suggest that children with ADHD are significantly more likely to develop substance use disorders than children without ADHD and that this increased risk is robust to demographic and methodological differences that varied across the studies. Finally, few studies addressed ADHD and comorbid disruptive behavior disorders (DBD), thus preventing a formal meta-analytic review. However, we qualitatively summarize the results of these studies and conclude that comorbid DBD complicates inferences about the specificity of ADHD effects on substance use outcomes.

Swim stress increases hippocampal Zif268 expression in the spontaneously hypertensive rat

The spontaneously hypertensive rat (SHR), which is used as an animal model of ADHD, displays numerous behavioural differences on learning and memory tasks. This study characterises differences in neural Zif268 expression in male SHR, Wistar Kyoto (WKY) and Sprague-Dawley (SD) rats after a 10-min forced swim. Swim stress increased Zif268 expression in the hippocampus of SHR only. In addition, SHR had increased expression in the prefrontal cortex, dorsal striatum and decreased expression in the nucleus accumbens shell in comparison to WKY and SD; and increased expression in the amygdala compared to SD. These findings: (i) support previous research indicating that SHR have altered neurobiological response to stressors, (ii) extends the characterisation of multiple memory systems in SHR to include differences in Zif268 expression in brain regions underlying their altered behaviour and (iii) supports previous findings that SHR may have a specific deficit within the shell of the nucleus accumbens.

Internalizing versus externalizing comorbidity: neural circuit hypothesis

The aim of the present study was to review and update historical controversies in relation to the limbic system in light of advances in the neuroanatmy and neurobiology of cortico-striatal-thalamic-cortical (CSTC) neural circuits. It is hypothesized that observed comorbidities between internalizing and externalizing childhood syndromes may be better understood in terms of excess communication between subcortical brain circuits. A neuroanatomical understanding of reciprocal and non-reciprocal connections between modular circuits provides a basis for understanding previously puzzling aspects of internalizing, externalizing comorbidity. Function depends on the degree of cooperative integration of goal orientation, Pavlovian stimulus response, and operant processing in cortical-subcortical circuits, and interventions may be targeted at any of these functions.

Morphological abnormalities of the thalamus in youths with attention deficit hyperactivity disorder

OBJECTIVE

The role of the thalamus in the genesis of attention deficit hyperactivity disorder (ADHD) remains poorly understood. The authors used anatomical MRI to examine the morphology of the thalamus in youths with ADHD and healthy comparison youths.

METHOD

The authors examined 46 youths with ADHD and 59 comparison youths 8-18 years of age in a cross-sectional case-control study. Conventional volumes and measures of surface morphology of the thalamus served as the main outcome measures.

RESULTS

A mixed-effects model comparing whole thalamic volumes revealed no significant differences between groups. Maps of the thalamic surface revealed significantly smaller regional volumes bilaterally in the pulvinar in youths with ADHD relative to comparison subjects. Post hoc analyses showed that ADHD patients who received stimulants (N=31) had larger conventional thalamic volumes than untreated youths with ADHD, and maps of the thalamic surface showed enlargement over the pulvinar in those receiving stimulants. Smaller regional volumes in the right lateral and left posterior thalamic surfaces were associated with more severe hyperactivity symptoms, whereas larger regional volumes in the right medial thalamic surfaces were associated with more severe symptoms of inattention.

CONCLUSION

These findings demonstrate reduced pulvinar volumes in youths with ADHD and indicate that this same area is relatively enlarged in patients treated with stimulants compared to those untreated. Associations of hyperactivity scores with smaller regional volumes on the lateral thalamic surface and inattention scores with larger regional volumes on the medial thalamic surface suggest the differential involvement of thalamic subcircuits in the pathogenesis of differing ADHD symptoms.

Sensory Over-Responsivity and ADHD: Differentiating Using Electrodermal Responses, Cortisol, and Anxiety

Deficits in sensory modulation have been linked clinically with impaired attention, arousal, and impulsivity for years, but a clear understanding of the relationship between sensory modulation disorders and attention deficit hyperactivity disorder (ADHD) has proven elusive. Our preliminary work suggested that patterns of salivary cortisol and electrodermal responsivity to sensation may be linked to different groups of children with ADHD; those with and without sensory over-responsivity (SOR). Additionally, SOR has been linked to anxiety, and anxiety has been linked to ADHD. A clearer understanding of the relationship between anxiety, SOR, and ADHD may support a better understanding of ADHD diagnostic subtypes. We examined neuroendocrine, electrodermal and behavioral characteristics and sought to predict group membership among 6- to 12-year-old children with ADHD and SOR (ADHDs), ADHD and no SOR (ADHDt), and typicals (TYP). Behavioral questionnaires were completed to document SOR and anxiety. Lab testing used a Sensory Challenge Protocol (SCP) with concurrent electrodermal measurement and the collection of cortisol prior to and following the SCP. Results substantiated links between SOR and anxiety, in both TYP and ADHD children. Results suggests that ADHD should be considered in conjunction with anxiety and sensory responsivity; both may be related to bottom-up processing differences, and deficits in prefrontal cortex/hippocampal synaptic gating.

Anxiety in boys with attention-deficit/hyperactivity disorder with and without chronic multiple tic disorder

OBJECTIVE

This study examined the psychosocial and behavioral concomitants of anxiety in clinic-referred boys with attention-deficit/hyperactivity disorder (ADHD) with and without chronic multiple tic disorder (CMTD).

METHOD

ADHD boys with (n = 65) and without (n = 94) CMTD were evaluated with measures of psychiatric symptoms, mental health risk factors, and academic and social performance.

RESULTS

Boys with CMTD evidenced more severe anxiety and less social competence and were more likely to be living with only one biological parent than the ADHD Only group, but the magnitude of group differences was generally small. The severity of generalized anxiety, separation anxiety, social phobia, and obsessive-compulsive symptoms were uniquely associated with a different pattern of risk factors, and there was some evidence that these patterns differed for the two groups of boys.

CONCLUSION

Boys with CMTD had a relatively more severe and complex pattern of anxiety that was associated with different clinical features, all of which suggests that ADHD plus CMTD might better be conceptualized as a distinct clinical entity from ADHD Only. However, findings from the extant literature are mixed, and therefore this remains a topic for further study.