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Pirnia B, Soleimani A, Farhoudian A, Zahiroddin A. The contribution of childhood maltreatment to the incidence of heavy cannabis use in Iran (IRNS-CCI): A multicenter, matched-pairs, nested, case-control study. CHILD ABUSE & NEGLECT 2024; 149:106632. [PMID: 38368781 DOI: 10.1016/j.chiabu.2024.106632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/24/2023] [Accepted: 01/01/2024] [Indexed: 02/20/2024]
Abstract
BACKGROUND Previous studies have shown the role of the interaction between the endocannabinoid system (ECS) and life's adversities in the formation of addiction, including alcohol abuse. OBJECTIVE Our objective was to identify childhood maltreatment (CM) patterns with the strongest impact on the probability of heavy cannabis use (THCCOOH concentrations ≥150 ng/mL) in Iran. PARTICIPANTS AND SETTING Using survivor sampling, 350 adult participants were selected, and they were then allocated to three categories based on an optimal algorithm: 1) Sexual abuse, 2) Physical abuse, and 3) Physical neglect. METHODS From 1 September 2019 to 1 May 2023, we implemented a multicenter, matched-pairs, nested, case-control study based on the wave 3-wave 6 data of a longitudinal, multicenter, cohort study. The cases and controls (n = 350 men) were defined according to the severity of CM. The THC potency was evaluated with the delta-9 carboxy tetrahydrocannabinol (THC-COOH) levels in urine using gas chromatography/mass spectrometry (GC/MS). We calculated the population attributable fractions (PAFs) to identify the patterns of maltreatment associated with the highest odds of high-potency cannabis use. RESULTS Accumulating CM, including sexual abuse, physical abuse, and physical neglect, carried more than three times the risk of heavy cannabis use (OR 3.4 95 % CI 2.9-4.1), and the combination of the three indicators of maltreatment and a high BMI (25-29.9) carried more than four times the risk of heavy cannabis use (OR 4.7 95 % CI 2.7-4.1) compared to the controls. We estimated that in the case of zero CM for each of the three indicators, over 20 % of new cases of heavy cannabis use can be prevented. CONCLUSIONS The findings show the significance of CM as a predicator of heavy cannabis use in adulthood and in the abstinence phase.
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Affiliation(s)
- Bijan Pirnia
- Department of Psychology, Faculty of Humanities, University of Science and Culture, Tehran, Iran
| | - Ali Soleimani
- Department of Psychology, Faculty of Humanities, University of Science and Culture, Tehran, Iran.
| | - Ali Farhoudian
- Department of Psychiatry, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Zahiroddin
- Department of Psychiatry, Behavioral Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Skumlien M, Freeman TP, Hall D, Mokrysz C, Wall MB, Ofori S, Petrilli K, Trinci K, Borissova A, Fernandez-Vinson N, Langley C, Sahakian BJ, Curran HV, Lawn W. The Effects of Acute Cannabis With and Without Cannabidiol on Neural Reward Anticipation in Adults and Adolescents. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2023; 8:219-229. [PMID: 36642667 DOI: 10.1016/j.bpsc.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/11/2022] [Accepted: 10/14/2022] [Indexed: 01/15/2023]
Abstract
BACKGROUND Adolescents may respond differently to cannabis than adults, yet no previous functional magnetic resonance imaging study has examined acute cannabis effects in this age group. In this study, we investigated the neural correlates of reward anticipation after acute exposure to cannabis in adolescents and adults. METHODS This was a double-blind, placebo-controlled, randomized, crossover experiment. Forty-seven adolescents (n = 24, 12 females, ages 16-17 years) and adults (n = 23, 11 females, ages 26-29 years) matched on cannabis use frequency (0.5-3 days/week) completed the Monetary Incentive Delay task during functional magnetic resonance imaging after inhaling cannabis with 0.107 mg/kg Δ⁹-tetrahydrocannabinol ("THC") (8 mg THC for a 75-kg person) or with THC plus 0.320 mg/kg cannabidiol ("THC+CBD") (24 mg CBD for a 75-kg person), or placebo cannabis. We investigated reward anticipation activity with whole-brain analyses and region of interest analyses in the right and left ventral striatum, right and left anterior cingulate cortex, and right insula. RESULTS THC reduced anticipation activity compared with placebo in the right (p = .005, d= 0.49) and left (p = .003, d = 0.50) ventral striatum and the right insula (p = .01, d = 0.42). THC+CBD reduced activity compared with placebo in the right ventral striatum (p = .01, d = 0.41) and right insula (p = .002, d = 0.49). There were no differences between "THC" and "THC+CBD" conditions and no significant drug by age group interaction effect, supported by Bayesian analyses. There were no significant effects in the whole-brain analyses. CONCLUSIONS In weekly cannabis users, cannabis suppresses the brain's anticipatory reward response to money, and CBD does not modulate this effect. Furthermore, the adolescent reward circuitry is not differentially sensitive to acute effects of cannabis on reward anticipation.
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Affiliation(s)
- Martine Skumlien
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom.
| | - Tom P Freeman
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom; Addiction and Mental Health Group, Department of Psychology, University of Bath, Bath, United Kingdom
| | - Daniel Hall
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom
| | - Claire Mokrysz
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom
| | - Matthew B Wall
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom; Invicro, London, United Kingdom; Faculty of Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Shelan Ofori
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom
| | - Kat Petrilli
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom; Addiction and Mental Health Group, Department of Psychology, University of Bath, Bath, United Kingdom
| | - Katie Trinci
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom
| | - Anna Borissova
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom; Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Natalia Fernandez-Vinson
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom
| | - Christelle Langley
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Barbara J Sahakian
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - H Valerie Curran
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom
| | - Will Lawn
- Clinical Psychopharmacology Unit, Clinical Educational and Health Psychology Department, University College London, London, United Kingdom; Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom; Department of Addictions, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
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Neutral CB1 Receptor Antagonists as Pharmacotherapies for Substance Use Disorders: Rationale, Evidence, and Challenge. Cells 2022; 11:cells11203262. [PMID: 36291128 PMCID: PMC9600259 DOI: 10.3390/cells11203262] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022] Open
Abstract
Cannabinoid receptor 1 (CB1R) has been one of the major targets in medication development for treating substance use disorders (SUDs). Early studies indicated that rimonabant, a selective CB1R antagonist with an inverse agonist profile, was highly promising as a therapeutic for SUDs. However, its adverse side effects, such as depression and suicidality, led to its withdrawal from clinical trials worldwide in 2008. Consequently, much research interest shifted to developing neutral CB1R antagonists based on the recognition that rimonabant’s side effects may be related to its inverse agonist profile. In this article, we first review rimonabant’s research background as a potential pharmacotherapy for SUDs. Then, we discuss the possible mechanisms underlying its therapeutic anti-addictive effects versus its adverse effects. Lastly, we discuss the rationale for developing neutral CB1R antagonists as potential treatments for SUDs, the supporting evidence in recent research, and the challenges of this strategy. We conclude that developing neutral CB1R antagonists without inverse agonist profile may represent attractive strategies for the treatment of SUDs.
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Skumlien M, Mokrysz C, Freeman TP, Wall MB, Bloomfield M, Lees R, Borissova A, Petrilli K, Carson J, Coughlan T, Ofori S, Langley C, Sahakian BJ, Curran HV, Lawn W. Neural responses to reward anticipation and feedback in adult and adolescent cannabis users and controls. Neuropsychopharmacology 2022; 47:1976-1983. [PMID: 35388175 PMCID: PMC9485226 DOI: 10.1038/s41386-022-01316-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 12/12/2022]
Abstract
Chronic use of drugs may alter the brain's reward system, though the extant literature concerning long-term cannabis use and neural correlates of reward processing has shown mixed results. Adolescents may be more vulnerable to the adverse effects of cannabis than adults; however, this has not been investigated for reward processing. As part of the 'CannTeen' study, in the largest functional magnetic resonance imaging study of reward processing and cannabis use to date, we investigated reward anticipation and feedback in 125 adult (26-29 years) and adolescent (16-17 years) cannabis users (1-7 days/week cannabis use) and gender- and age-matched controls, using the Monetary Incentive Delay task. Blood-oxygen-level-dependent responses were examined using region of interest (ROI) analyses in the bilateral ventral striatum for reward anticipation and right ventral striatum and left ventromedial prefrontal cortex for feedback, and exploratory whole-brain analyses. Results showed no User-Group or User-Group × Age-Group effects during reward anticipation or feedback in pre-defined ROIs. These null findings were supported by post hoc Bayesian analyses. However, in the whole-brain analysis, cannabis users had greater feedback activity in the prefrontal and inferior parietal cortex compared to controls. In conclusion, cannabis users and controls had similar neural responses during reward anticipation and in hypothesised reward-related regions during reward feedback. The whole-brain analysis revealed tentative evidence of greater fronto-parietal activity in cannabis users during feedback. Adolescents showed no increased vulnerability compared with adults. Overall, reward anticipation and feedback processing appear spared in adolescent and adult cannabis users, but future longitudinal studies are needed to corroborate this.
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Affiliation(s)
- Martine Skumlien
- Department of Psychiatry, University of Cambridge, Cambridge, UK.
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK.
| | - Claire Mokrysz
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
| | - Tom P Freeman
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
- Addiction and Mental Health Group (AIM), Department of Psychology, University of Bath, Bath, UK
| | - Matthew B Wall
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
- Invicro, London, UK
- Faculty of Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | | | - Rachel Lees
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
- Addiction and Mental Health Group (AIM), Department of Psychology, University of Bath, Bath, UK
| | - Anna Borissova
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
| | - Kat Petrilli
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
- Addiction and Mental Health Group (AIM), Department of Psychology, University of Bath, Bath, UK
| | - James Carson
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
| | - Tiernan Coughlan
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
| | - Shelan Ofori
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
| | - Christelle Langley
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Barbara J Sahakian
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - H Valerie Curran
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
| | - Will Lawn
- Clinical Psychopharmacology Unit, Clinical, Educational and Health Psychology Department, University College London, London, UK
- National Addiction Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
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5
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Murray CH, Glazer JE, Lee R, Nusslock R, de Wit H. Δ9-THC reduces reward-related brain activity in healthy adults. Psychopharmacology (Berl) 2022; 239:2829-2840. [PMID: 35612654 PMCID: PMC10560585 DOI: 10.1007/s00213-022-06164-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/12/2022] [Indexed: 10/18/2022]
Abstract
RATIONALE Greater availability of cannabis in the USA has raised concerns about adverse effects of the drug, including possible amotivational states. Lack of motivation may be assessed by examining acute effects of cannabinoids on reward processing. OBJECTIVES This study examined single doses of delta-9-tetrahydrocannabinol (∆9-THC; 7.5, 15 mg oral) in healthy adults using a version of the monetary incentive delay (MID) task adapted for electroencephalography (EEG; e-MID) in a within-subjects, double blind design. METHODS Two phases of reward processing were examined: anticipation, which occurs with presentation of cues that indicate upcoming reward, punishment, or neutral conditions, and outcome, which occurs with feedback indicating hits or misses. During anticipation, we measured two event-related potential (ERP) components: the P300, which measures attention and motivation, and the LPP, which measures affective processing. During outcome processing, we measured P300 and LPP, as well as the RewP, which measures outcome evaluation. RESULTS We found that ∆9-THC modulated outcome processing, but not reward anticipation. Specifically, both doses of ∆9-THC (7.5 and 15 mg) reduced RewP amplitudes after outcome feedback (hits and misses) relative to placebo. ∆9-THC (15 mg) also reduced P300 and LPP amplitudes following hits compared to misses, relative to both placebo and 7.5 mg ∆9-THC. CONCLUSIONS These findings suggest that ∆9-THC dampens responses to both reward and loss feedback, which may reflect an "amotivational" state. Future studies are needed to determine generalizability of this effect, such as its pharmacological specificity and its specificity to monetary vs other types of reward.
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Affiliation(s)
- Conor H Murray
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, MC3077, Chicago, IL, 60637, USA
| | - James E Glazer
- Department of Psychology, Northwestern University, 2029 Sheridan Road, Evanston, IL, 60208, USA
| | - Royce Lee
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, MC3077, Chicago, IL, 60637, USA
| | - Robin Nusslock
- Department of Psychology, Northwestern University, 2029 Sheridan Road, Evanston, IL, 60208, USA
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, MC3077, Chicago, IL, 60637, USA.
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Bilbao A, Spanagel R. Medical cannabinoids: a pharmacology-based systematic review and meta-analysis for all relevant medical indications. BMC Med 2022; 20:259. [PMID: 35982439 PMCID: PMC9389720 DOI: 10.1186/s12916-022-02459-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 07/01/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Medical cannabinoids differ in their pharmacology and may have different treatment effects. We aimed to conduct a pharmacology-based systematic review (SR) and meta-analyses of medical cannabinoids for efficacy, retention and adverse events. METHODS We systematically reviewed (registered at PROSPERO: CRD42021229932) eight databases for randomized controlled trials (RCTs) of dronabinol, nabilone, cannabidiol and nabiximols for chronic pain, spasticity, nausea /vomiting, appetite, ALS, irritable bowel syndrome, MS, Chorea Huntington, epilepsy, dystonia, Parkinsonism, glaucoma, ADHD, anorexia nervosa, anxiety, dementia, depression, schizophrenia, PTSD, sleeping disorders, SUD and Tourette. Main outcomes and measures included patient-relevant/disease-specific outcomes, retention and adverse events. Data were calculated as standardized mean difference (SMD) and ORs with confidence intervals (CI) via random effects. Evidence quality was assessed by the Cochrane Risk of Bias and GRADE tools. RESULTS In total, 152 RCTs (12,123 participants) were analysed according to the type of the cannabinoid, outcome and comparator used, resulting in 84 comparisons. Significant therapeutic effects of medical cannabinoids show a large variability in the grade of evidence that depends on the type of cannabinoid. CBD has a significant therapeutic effect for epilepsy (SMD - 0.5[CI - 0.62, - 0.38] high grade) and Parkinsonism (- 0.41[CI - 0.75, - 0.08] moderate grade). There is moderate evidence for dronabinol for chronic pain (- 0.31[CI - 0.46, - 0.15]), appetite (- 0.51[CI - 0.87, - 0.15]) and Tourette (- 1.01[CI - 1.58, - 0.44]) and moderate evidence for nabiximols on chronic pain (- 0.25[- 0.37, - 0.14]), spasticity (- 0.36[CI - 0.54, - 0.19]), sleep (- 0.24[CI - 0.35, - 0.14]) and SUDs (- 0.48[CI - 0.92, - 0.04]). All other significant therapeutic effects have either low, very low, or even no grade of evidence. Cannabinoids produce different adverse events, and there is low to moderate grade of evidence for this conclusion depending on the type of cannabinoid. CONCLUSIONS Cannabinoids are effective therapeutics for several medical indications if their specific pharmacological properties are considered. We suggest that future systematic studies in the cannabinoid field should be based upon their specific pharmacology.
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Affiliation(s)
- Ainhoa Bilbao
- Behavioral Genetics Research Group, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, Mannheim, Germany.
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, Mannheim, Germany
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Molecular Alterations of the Endocannabinoid System in Psychiatric Disorders. Int J Mol Sci 2022; 23:ijms23094764. [PMID: 35563156 PMCID: PMC9104141 DOI: 10.3390/ijms23094764] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 02/07/2023] Open
Abstract
The therapeutic benefits of the current medications for patients with psychiatric disorders contrast with a great variety of adverse effects. The endocannabinoid system (ECS) components have gained high interest as potential new targets for treating psychiatry diseases because of their neuromodulator role, which is essential to understanding the regulation of many brain functions. This article reviewed the molecular alterations in ECS occurring in different psychiatric conditions. The methods used to identify alterations in the ECS were also described. We used a translational approach. The animal models reproducing some behavioral and/or neurochemical aspects of psychiatric disorders and the molecular alterations in clinical studies in post-mortem brain tissue or peripheral tissues were analyzed. This article reviewed the most relevant ECS changes in prevalent psychiatric diseases such as mood disorders, schizophrenia, autism, attentional deficit, eating disorders (ED), and addiction. The review concludes that clinical research studies are urgently needed for two different purposes: (1) To identify alterations of the ECS components potentially useful as new biomarkers relating to a specific disease or condition, and (2) to design new therapeutic targets based on the specific alterations found to improve the pharmacological treatment in psychiatry.
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Ramaekers JG, Theunissen EL, van Ruitenbeek P, Mason NL. Cannabis Use and Neuroadaptation: A Call for Δ 9 -Tetrahydrocannabinol Challenge Studies. Front Psychiatry 2022; 13:870750. [PMID: 35492732 PMCID: PMC9046729 DOI: 10.3389/fpsyt.2022.870750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 02/18/2022] [Indexed: 11/26/2022] Open
Abstract
Currently, the assessment of the neurobehavioral consequences of repeated cannabis use is restricted to studies in which brain function of chronic cannabis users is compared to that of non-cannabis using controls. The assumption of such studies is that changes in brain function of chronic users are caused by repeated and prolonged exposure to acute cannabis intoxication. However, differences in brain function between chronic cannabis users and non-users might also arise from confounding factors such as polydrug use, alcohol use, withdrawal, economic status, or lifestyle conditions. We propose a methodology that highlights the relevance of acute Δ9-tetrahydrocannabinol (THC) dosing studies for a direct assessment of neuroadaptations in chronic cannabis users. The approach includes quantification of neurochemical, receptor, and functional brain network changes in response to an acute cannabis challenge, as well as stratification of cannabis using groups ranging from occasional to cannabis-dependent individuals. The methodology allows for an evaluation of THC induced neuroadaptive and neurocognitive changes across cannabis use history, that can inform neurobiological models on reward driven, compulsive cannabis use.
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Affiliation(s)
- Johannes G Ramaekers
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Eef L Theunissen
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Peter van Ruitenbeek
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Natasha L Mason
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
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Abstract
BACKGROUND Evidence suggests that an overlap exists between the neurobiology of psychotic disorders and the effects of cannabinoids on neurocognitive and neurochemical substrates involved in reward processing. AIMS We investigate whether the psychotomimetic effects of delta-9-tetrahydrocannabinol (THC) and the antipsychotic potential of cannabidiol (CBD) are underpinned by their effects on the reward system and dopamine. METHODS This narrative review focuses on the overlap between altered dopamine signalling and reward processing induced by cannabinoids, pre-clinically and in humans. A systematic search was conducted of acute cannabinoid drug-challenge studies using neuroimaging in healthy subjects and those with psychosis RESULTS: There is evidence of increased striatal presynaptic dopamine synthesis and release in psychosis, as well as abnormal engagement of the striatum during reward processing. Although, acute THC challenges have elicited a modest effect on striatal dopamine, cannabis users generally indicate impaired presynaptic dopaminergic function. Functional MRI studies have identified that a single dose of THC may modulate regions involved in reward and salience processing such as the striatum, midbrain, insular, and anterior cingulate, with some effects correlating with the severity of THC-induced psychotic symptoms. CBD may modulate brain regions involved in reward/salience processing in an opposite direction to that of THC. CONCLUSIONS There is evidence to suggest modulation of reward processing and its neural substrates by THC and CBD. Whether such effects underlie the psychotomimetic/antipsychotic effects of these cannabinoids remains unclear. Future research should address these unanswered questions to understand the relationship between endocannabinoid dysfunction, reward processing abnormalities, and psychosis.
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Skumlien M, Langley C, Lawn W, Voon V, Curran HV, Roiser JP, Sahakian BJ. The acute and non-acute effects of cannabis on reward processing: A systematic review. Neurosci Biobehav Rev 2021; 130:512-528. [PMID: 34509513 DOI: 10.1016/j.neubiorev.2021.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 08/11/2021] [Accepted: 09/05/2021] [Indexed: 12/14/2022]
Abstract
Cannabis use has historically been thought to cause amotivation, but the relationship between cannabis and apathy, anhedonia, and reward processing remains poorly characterised. In this systematic review, we evaluated whether cannabis exposure acutely and/or non-acutely was associated with altered reward processing using questionnaire, behavioural, or functional neuroimaging measures. Questionnaire studies demonstrated greater anhedonia in adolescent cannabis users, and some indication of greater apathy in young adult cannabis users. Behavioural studies yielded some evidence of reduced reward learning in adolescent cannabis users, though there were too few studies in this category for reliable conclusions. Finally, longitudinal and acute functional neuroimaging studies showed an association between cannabis and blunted neural responses to reward, which did not emerge consistently in cross-sectional studies. The current results suggest that cannabis use is associated with specific impairments in reward and motivation. Future large-scale, longitudinal studies which use multiple behavioural and neuroimaging measures of reward processing may further clarify the impact of cannabis use on motivational and reward processes, and neural networks.
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Affiliation(s)
- Martine Skumlien
- Department of Psychiatry, University of Cambridge, Cambridge, UK.
| | | | - Will Lawn
- Clinical Psychopharmacology Unit, University College London, London, UK
| | - Valerie Voon
- Department of Psychiatry, University of Cambridge, Cambridge, UK; Behavioural and Clinical Neurosciences Institute, Cambridge, UK; Cambridgeshire and Peterborough NHS Trust, Cambridge, UK
| | - H Valerie Curran
- Clinical Psychopharmacology Unit, University College London, London, UK
| | - Jonathan P Roiser
- Institute of Cognitive Neuroscience, University College London, London, UK
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Spanagel R, Bilbao A. Approved cannabinoids for medical purposes - Comparative systematic review and meta-analysis for sleep and appetite. Neuropharmacology 2021; 196:108680. [PMID: 34181977 DOI: 10.1016/j.neuropharm.2021.108680] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/18/2021] [Accepted: 06/20/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND Cannabinoids are used for numerous disease indications. However, cannabinoids can also produce adverse effects; for example, they can disturb physiological functions such as sleep and appetite. The medical use of cannabinoids refers to a wide variety of preparations and products. Approved cannabinoid products include dronabinol ((-)-trans-Δ9-tetrahydrocannabinol (THC), nabilone (a THC analogue), and cannabidiol (CBD) that differ in their pharmacology and may thus have different adverse effects on sleep and appetite. OBJECTIVES Here we ask if (i) cannabinoids decrease sleep and appetite in somatic patients or patients that suffer from mental illness and if (ii) there is a difference between THC products (nabilone, dronabinol), vs. CBD in disturbing these physiological functions. METHODS In order to answer these two questions, we performed a comparative systematic review (SR) for nabilone, dronabinol, and CBD. For the comparative SR we searched PubMed, Medline, Embase, and PsycINFO for randomized controlled trials (RCTs) and extracted information for adverse side effects or outcomes reporting a negative impact on sleep and appetite. RCT evidence was calculated as odds ratios (ORs) via fixed effects meta-analyses. Evidence quality was assessed by the Cochrane Risk of Bias and GRADE tools. This study is registered at PROSPERO (CRD42021229932). FINDINGS A total of 17 RCTs (n = 1479) and 15 RCTs (n = 1974) were included for sleep and appetite, respectively. Pharmaceutical THC (nabilone, dronabinol) does not affect sleep or appetite. In contrast, there is moderate evidence that CBD decreases appetite (OR = 2.46 [1.74:4.01] but has also no effect on sleep. INTERPRETATIONS Our comparative systematic study shows that approved cannabinoids can decrease appetite as a negative side effect - an effect that seems to be driven by CBD. Approved cannabinoid products do not negatively affect sleep in somatic and psychiatric patients. This article is part of the special Issue on "Cannabinoids".
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Affiliation(s)
- Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, Germany.
| | - Ainhoa Bilbao
- Behavioral Genetics Research Group, Central Institute of Mental Health, Germany.
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12
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Gunasekera B, Davies C, Martin-Santos R, Bhattacharyya S. The Yin and Yang of Cannabis: A Systematic Review of Human Neuroimaging Evidence of the Differential Effects of Δ 9-Tetrahydrocannabinol and Cannabidiol. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2021; 6:636-645. [PMID: 33414100 DOI: 10.1016/j.bpsc.2020.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/14/2020] [Accepted: 10/19/2020] [Indexed: 12/23/2022]
Abstract
Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) have been the most investigated cannabinoids at the human and preclinical levels, although the neurobiological mechanisms underlying their effects remain unclear. Human experimental evidence complemented by observational studies suggests that THC may have psychotogenic effects while CBD may have antipsychotic effects. However, whether their effects on brain function are consistent with their opposing behavioral effects remains unclear. To address this, here we synthesize neuroimaging evidence investigating the acute effects of THC and CBD on human brain function using a range of neuroimaging techniques, with an aim to identify the key brain substrates where THC and CBD have opposing effects. After a systematic search, a review of the available studies indicated marked heterogeneity. However, an overall pattern of opposite effect profiles of the two cannabinoids was evident with some degree of consistency, primarily attributed to the head-to-head challenge studies of THC and CBD. While head-to-head comparisons are relatively few, collectively the evidence suggests that opposite effects of THC and CBD may be present in the striatum, parahippocampus, anterior cingulate/medial prefrontal cortex, and amygdala, with opposite effects less consistently identified in other regions. Broadly, THC seems to increase brain activation and blood flow, whereas CBD seems to decrease brain activation and blood flow. Given the sparse evidence, there is a particular need to understand the mechanisms underlying their opposite behavioral effects because it may not only offer insights into the underlying pathophysiological mechanisms of psychotic disorders but also suggest potentially novel targets and biomarkers for drug discovery.
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Affiliation(s)
- Brandon Gunasekera
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom
| | - Cathy Davies
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom
| | - Rocio Martin-Santos
- Department of Medicine, Institute of Neuroscience, University of Barcelona, Spain
| | - Sagnik Bhattacharyya
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom.
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13
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The why behind the high: determinants of neurocognition during acute cannabis exposure. Nat Rev Neurosci 2021; 22:439-454. [PMID: 34045693 DOI: 10.1038/s41583-021-00466-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2021] [Indexed: 11/08/2022]
Abstract
Acute cannabis intoxication may induce neurocognitive impairment and is a possible cause of human error, injury and psychological distress. One of the major concerns raised about increasing cannabis legalization and the therapeutic use of cannabis is that it will increase cannabis-related harm. However, the impairing effect of cannabis during intoxication varies among individuals and may not occur in all users. There is evidence that the neurocognitive response to acute cannabis exposure is driven by changes in the activity of the mesocorticolimbic and salience networks, can be exacerbated or mitigated by biological and pharmacological factors, varies with product formulations and frequency of use and can differ between recreational and therapeutic use. It is argued that these determinants of the cannabis-induced neurocognitive state should be taken into account when defining and evaluating levels of cannabis impairment in the legal arena, when prescribing cannabis in therapeutic settings and when informing society about the safe and responsible use of cannabis.
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14
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Morie KP, Potenza MN. A Mini-Review of Relationships Between Cannabis Use and Neural Foundations of Reward Processing, Inhibitory Control and Working Memory. Front Psychiatry 2021; 12:657371. [PMID: 33967859 PMCID: PMC8100188 DOI: 10.3389/fpsyt.2021.657371] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/29/2021] [Indexed: 01/26/2023] Open
Abstract
Cannabis is commonly used, and use may be increasing in the setting of increasing legalization and social acceptance. The scope of the effects of cannabis products, including varieties with higher or lower levels of Δ9-tetrahydrocannabinol (THC) or cannabidiol (CBD), on domains related to addictive behavior deserves attention, particularly as legalization continues. Cannabis use may impact neural underpinnings of cognitive functions linked to propensities to engage in addictive behaviors. Here we consider these neurocognitive processes within the framework of the dual-process model of addictions. In this mini-review, we describe data on the relationships between two main constituents of cannabis (THC and CBD) and neural correlates of reward processing, inhibitory control and working memory.
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Affiliation(s)
- Kristen P. Morie
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
- Child Study Center, Yale University School of Medicine, New Haven, CT, United States
| | - Marc N. Potenza
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
- Child Study Center, Yale University School of Medicine, New Haven, CT, United States
- Connecticut Mental Health Center, New Haven, CT, United States
- Connecticut Council on Problem Gambling, Wethersfield, CT, United States
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
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15
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A systematic review of neuroimaging and acute cannabis exposure in age-of-risk for psychosis. Transl Psychiatry 2021; 11:217. [PMID: 33850098 PMCID: PMC8044224 DOI: 10.1038/s41398-021-01295-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/06/2021] [Accepted: 02/05/2021] [Indexed: 01/14/2023] Open
Abstract
Acute exposure to cannabis has been associated with an array of cognitive alterations, increased risk for neuropsychiatric illness, and other neuropsychiatric sequelae including the emergence of acute psychotic symptoms. However, the brain alterations associating cannabis use and these behavioral and clinical phenotypes remains disputed. To this end, neuroimaging can be a powerful technique to non-invasively study the impact of cannabis exposure on brain structure and function in both humans and animal models. While chronic exposure studies provide insight into how use may be related to long-term outcomes, acute exposure may reveal interesting information regarding the immediate impact of use and abuse on brain circuits. Understanding these alterations could reveal the connection with symptom dimensions in neuropsychiatric disorders and, more specifically with psychosis. The purpose of the present review is to: 1) provide an update on the findings of pharmacological neuroimaging studies examining the effects of administered cannabinoids and 2) focus the discussion on studies that examine the sensitive window for the emergence of psychosis. Current literature indicates that cannabis exposure has varied effects on the brain, with the principal compounds in cannabis (delta-9-tetrahydrocannabinol and cannabidiol) altering activity across different brain regions. Importantly, we also discovered critical gaps in the literature, particularly regarding sex-dependent responses and long-term effects of chronic exposure. Certain networks often characterized as dysregulated in psychosis, like the default mode network and limbic system, were also impacted by THC exposure, identifying areas of particular interest for future work investigating the potential relationship between the two.
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16
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Arsalidou M, Vijayarajah S, Sharaev M. Basal ganglia lateralization in different types of reward. Brain Imaging Behav 2021; 14:2618-2646. [PMID: 31927758 DOI: 10.1007/s11682-019-00215-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Reward processing is a fundamental human activity. The basal ganglia are recognized for their role in reward processes; however, specific roles of the different nuclei (e.g., nucleus accumbens, caudate, putamen and globus pallidus) remain unclear. Using quantitative meta-analyses we assessed whole-brain and basal ganglia specific contributions to money, erotic, and food reward processing. We analyzed data from 190 fMRI studies which reported stereotaxic coordinates of whole-brain, within-group results from healthy adult participants. Results showed concordance in overlapping and distinct cortical and sub-cortical brain regions as a function of reward type. Common to all reward types was concordance in basal ganglia nuclei, with distinct differences in hemispheric dominance and spatial extent in response to the different reward types. Food reward processing favored the right hemisphere; erotic rewards favored the right lateral globus pallidus and left caudate body. Money rewards engaged the basal ganglia bilaterally including its most anterior part, nucleus accumbens. We conclude by proposing a model of common reward processing in the basal ganglia and separate models for money, erotic, and food rewards.
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Affiliation(s)
- Marie Arsalidou
- Department of Psychology, National Research University Higher School of Economics, Moscow, Russian Federation. .,Department of Psychology, Faculty of Health, York University, Toronto, ON, Canada.
| | - Sagana Vijayarajah
- Department of Psychology, Faculty of Arts and Science, University of Toronto, Toronto, ON, Canada
| | - Maksim Sharaev
- Skolkovo Institute of Science and Technology, Moscow, Russian Federation
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17
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Qiu Z, Wang J. A voxel-wise meta-analysis of task-based functional MRI studies on impaired gain and loss processing in adults with addiction. J Psychiatry Neurosci 2021; 46:E128-E146. [PMID: 33185525 PMCID: PMC7955844 DOI: 10.1503/jpn.200047] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Disturbances in gain and loss processing have been extensively reported in adults with addiction, a brain disorder characterized by obsession with addictive substances or behaviours. Previous studies have provided conflicting results with respect to neural abnormalities in gain processing in addiction, and few investigations into loss processing. METHODS We conducted voxel-wise meta-analyses of abnormal task-evoked regional activities in adults with substance dependence and gambling addiction during the processing of gains and losses not related to their addiction (mainly monetary). We identified 24 studies, including 465 participants with substance dependence, 81 with gambling addiction and 490 healthy controls. RESULTS Compared with healthy controls, all participants with addictions showed hypoactivations in the prefrontal cortex, striatum and insula and hyperactivations in the default mode network during gain anticipation; hyperactivations in the prefrontal cortex and both hyper- and hypoactivations in the striatum during loss anticipation; and hyperactivations in the occipital lobe during gain outcome. In the substance dependence subgroup, activity in the occipital lobe was increased during gain anticipation but decreased during loss anticipation. LIMITATIONS We were unable to conduct meta-analyses in the gambling addiction subgroup because of a limited data set. We did not investigate the effects of clinical variables because of limited information. CONCLUSION The current study identified altered brain activity associated with higher- and lower-level function during gain and loss processing for non-addiction (mainly monetary) stimuli in adults with substance dependence and gambling addiction. Adults with addiction were more sensitive to anticipatory gains than losses at higher- and lower-level brain areas. These results may help us to better understand the pathology of gain and loss processing in addiction.
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Affiliation(s)
- Zeguo Qiu
- From the Department of Applied Psychology, Guangdong University of Foreign Studies, Guangzhou 510006, China (Qiu, Wang); and the School of Psychology, The University of Queensland, Brisbane 4067, Australia (Qiu)
| | - Junjing Wang
- From the Department of Applied Psychology, Guangdong University of Foreign Studies, Guangzhou 510006, China (Qiu, Wang); and the School of Psychology, The University of Queensland, Brisbane 4067, Australia (Qiu)
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18
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Lawn W, Hill J, Hindocha C, Yim J, Yamamori Y, Jones G, Walker H, Green SF, Wall MB, Howes OD, Curran HV, Freeman TP, Bloomfield MAP. The acute effects of cannabidiol on the neural correlates of reward anticipation and feedback in healthy volunteers. J Psychopharmacol 2020; 34:969-980. [PMID: 32755273 PMCID: PMC7745615 DOI: 10.1177/0269881120944148] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Cannabidiol has potential therapeutic benefits for people with psychiatric disorders characterised by reward function impairment. There is existing evidence that cannabidiol may influence some aspects of reward processing. However, it is unknown whether cannabidiol acutely affects brain function underpinning reward anticipation and feedback. HYPOTHESES We predicted that cannabidiol would augment brain activity associated with reward anticipation and feedback. METHODS We administered a single 600 mg oral dose of cannabidiol and matched placebo to 23 healthy participants in a double-blind, placebo-controlled, repeated-measures design. We employed the monetary incentive delay task during functional magnetic resonance imaging to assay the neural correlates of reward anticipation and feedback. We conducted whole brain analyses and region-of-interest analyses in pre-specified reward-related brain regions. RESULTS The monetary incentive delay task elicited expected brain activity during reward anticipation and feedback, including in the insula, caudate, nucleus accumbens, anterior cingulate and orbitofrontal cortex. However, across the whole brain, we did not find any evidence that cannabidiol altered reward-related brain activity. Moreover, our Bayesian analyses showed that activity in our regions-of-interest was similar following cannabidiol and placebo. Additionally, our behavioural measures of motivation for reward did not show a significant difference between cannabidiol and placebo. DISCUSSION Cannabidiol did not acutely affect the neural correlates of reward anticipation and feedback in healthy participants. Future research should explore the effects of cannabidiol on different components of reward processing, employ different doses and administration regimens, and test its reward-related effects in people with psychiatric disorders.
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Affiliation(s)
- Will Lawn
- Clinical Psychopharmacology Unit, University College London, London, UK
| | - James Hill
- Translational Psychiatry Research Group, University College London, London, UK
| | - Chandni Hindocha
- Clinical Psychopharmacology Unit, University College London, London, UK
- Translational Psychiatry Research Group, University College London, London, UK
- NIHR University College London Hospitals Biomedical Research Centre, University College Hospital, London, UK
| | - Jocelyn Yim
- Translational Psychiatry Research Group, University College London, London, UK
| | - Yumeya Yamamori
- Translational Psychiatry Research Group, University College London, London, UK
- Institute of Cognitive Neuroscience, University College London, London, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Gus Jones
- Translational Psychiatry Research Group, University College London, London, UK
| | - Hannah Walker
- Translational Psychiatry Research Group, University College London, London, UK
| | - Sebastian F Green
- Translational Psychiatry Research Group, University College London, London, UK
| | - Matthew B Wall
- Clinical Psychopharmacology Unit, University College London, London, UK
- Invicro London, Hammersmith Hospital, London, UK
| | - Oliver D Howes
- Psychiatric Imaging Group, Imperial College London, London, UK
| | - H Valerie Curran
- Clinical Psychopharmacology Unit, University College London, London, UK
- NIHR University College London Hospitals Biomedical Research Centre, University College Hospital, London, UK
| | - Tom P Freeman
- Clinical Psychopharmacology Unit, University College London, London, UK
- Translational Psychiatry Research Group, University College London, London, UK
- Addiction and Mental Health Group (AIM), University of Bath, Bath, UK
- National Addiction Centre, Institute of Psychiatry, Psychology and Neuroscience, London, UK
| | - Michael AP Bloomfield
- Clinical Psychopharmacology Unit, University College London, London, UK
- Translational Psychiatry Research Group, University College London, London, UK
- NIHR University College London Hospitals Biomedical Research Centre, University College Hospital, London, UK
- Psychiatric Imaging Group, Imperial College London, London, UK
- The Traumatic Stress Clinic, St Pancras Hospital, London, UK
- National Hospital for Neurology and Neurosurgery, London, UK
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19
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Lawn W, Freeman TP, East K, Gaule A, Aston ER, Bloomfield MAP, Das RK, Morgan CJA, Curran HV. The Acute Effects of a Dopamine D3 Receptor Preferring Agonist on Motivation for Cigarettes in Dependent and Occasional Cigarette Smokers. Nicotine Tob Res 2019; 20:800-809. [PMID: 29065193 PMCID: PMC5991206 DOI: 10.1093/ntr/ntx159] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 07/12/2017] [Indexed: 12/13/2022]
Abstract
Background Dopaminergic functioning is thought to play critical roles in both motivation and addiction. There is preliminary evidence that dopamine agonists reduce the motivation for cigarettes in smokers. However, the effects of pramipexole, a dopamine D3 receptor preferring agonist, have not been investigated. The aim of this study was to examine the effects of an acute dose of pramipexole on the motivation to earn cigarettes and nondrug rewards. Methods Twenty dependent and 20 occasional smokers received 0.5 mg pramipexole using a double-blind, placebo-controlled crossover design. Motivation for cigarettes and consummatory nondrug rewards was measured using the DReaM-Choice task, in which participants earned, and later “consumed,” cigarettes, music, and chocolate. Demand for cigarettes was measured using the Cigarette Purchase Task (CPT). Self-reported craving, withdrawal, and drug effects were also recorded. Results Dependent smokers chose (p < .001) and button-pressed for (p < .001) cigarettes more, and chose chocolate less (p < .001), than occasional smokers. Pramipexole did not affect the number of choices for or amount of button-pressing for any reward including cigarettes, which was supported by a Bayesian analysis. The dependent smokers had greater demand for cigarettes than occasional smokers across all CPT outcomes (ps < .021), apart from elasticity. Pramipexole did not affect demand for cigarettes, and this was supported by Bayesian analyses. Pramipexole produced greater subjective “feel drug” and “dislike drug” effects than placebo. Conclusions Dependent and occasional cigarette smokers differed in their motivation for cigarettes but not for the nondrug rewards. Pramipexole did not acutely alter motivation for cigarettes. These findings question the role of dopamine D3 receptors in cigarette-seeking behavior in dependent and occasional smokers. Implications This study adds to the growing literature about cigarette versus nondrug reward processing in nicotine dependence and the role of dopamine in cigarette-seeking behavior. Our results suggest nicotine dependence is associated with a hypersensitivity to cigarette rewards but not a hyposensitivity to nondrug rewards. Furthermore, our results question the importance of dopamine D3 receptors in motivational processing of cigarettes in occasional and dependent smokers.
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Affiliation(s)
- Will Lawn
- Clinical Psychopharmacology unit, University College London, London, UK
| | - Tom P Freeman
- Clinical Psychopharmacology unit, University College London, London, UK.,Addictions Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Katie East
- Addictions Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Annie Gaule
- Clinical Psychopharmacology unit, University College London, London, UK
| | - Elizabeth R Aston
- Center for Alcohol and Addiction Studies, Brown University School of Public Health, Providence, RI
| | - Michael A P Bloomfield
- Clinical Psychopharmacology unit, University College London, London, UK.,Psychiatric Imaging Group, Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, UK.,Division of Psychiatry, University College London, Maple House, London, UK
| | - Ravi K Das
- Clinical Psychopharmacology unit, University College London, London, UK
| | - Celia J A Morgan
- Clinical Psychopharmacology unit, University College London, London, UK.,Department of Psychology, University of Exeter, Washington Singer Building, Exeter, UK
| | - H Valerie Curran
- Clinical Psychopharmacology unit, University College London, London, UK
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20
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Just AL, Meng C, Smith DG, Bullmore ET, Robbins TW, Ersche KD. Effects of familial risk and stimulant drug use on the anticipation of monetary reward: an fMRI study. Transl Psychiatry 2019; 9:65. [PMID: 30718492 PMCID: PMC6362203 DOI: 10.1038/s41398-019-0399-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 10/19/2018] [Accepted: 12/09/2018] [Indexed: 12/12/2022] Open
Abstract
The association between stimulant drug use and aberrant reward processing is well-documented in the literature, but the nature of these abnormalities remains elusive. The present study aims to disentangle the separate and interacting effects of stimulant drug use and pre-existing familial risk on abnormal reward processing associated with stimulant drug addiction. We used the Monetary Incentive Delay task, a well-validated measure of reward processing, during fMRI scanning in four distinct groups: individuals with familial risk who were either stimulant drug-dependent (N = 41) or had never used stimulant drugs (N = 46); and individuals without familial risk who were either using stimulant drugs (N = 25) or not (N = 48). We first examined task-related whole-brain activation followed by a psychophysiological interaction analysis to further explore brain functional connectivity. For analyses, we used a univariate model with two fixed factors (familial risk and stimulant drug use). Our results showed increased task-related activation in the putamen and motor cortex of stimulant-using participants. We also found altered task-related functional connectivity between the putamen and frontal regions in participants with a familial risk (irrespective of whether they were using stimulant drugs or not). Additionally, we identified an interaction between stimulant drug use and familial risk in task-related functional connectivity between the putamen and motor-related cortical regions in potentially at-risk individuals. Our findings suggest that abnormal task-related activation in motor brain systems is associated with regular stimulant drug use, whereas abnormal task-related functional connectivity in frontostriatal brain systems, in individuals with familial risk, may indicate pre-existing neural vulnerability for developing addiction.
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Affiliation(s)
- Alanna L. Just
- 0000000121885934grid.5335.0Departments of Psychiatry and Psychology, University of Cambridge, Cambridge, UK ,0000000121885934grid.5335.0Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Chun Meng
- 0000000121885934grid.5335.0Departments of Psychiatry and Psychology, University of Cambridge, Cambridge, UK ,0000000121885934grid.5335.0Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Dana G. Smith
- 0000000121885934grid.5335.0Departments of Psychiatry and Psychology, University of Cambridge, Cambridge, UK ,0000000121885934grid.5335.0Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Edward T. Bullmore
- 0000000121885934grid.5335.0Departments of Psychiatry and Psychology, University of Cambridge, Cambridge, UK ,0000000121885934grid.5335.0Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK ,0000 0004 0412 9303grid.450563.1Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK ,0000 0001 2162 0389grid.418236.aGlaxoSmithKline, Immuno-Inflammation Therapeutic Area Unit, Stevenage, UK
| | - Trevor W. Robbins
- 0000000121885934grid.5335.0Departments of Psychiatry and Psychology, University of Cambridge, Cambridge, UK ,0000000121885934grid.5335.0Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Karen D. Ersche
- 0000000121885934grid.5335.0Departments of Psychiatry and Psychology, University of Cambridge, Cambridge, UK ,0000000121885934grid.5335.0Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
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21
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Bloomfield MAP, Hindocha C, Green SF, Wall MB, Lees R, Petrilli K, Costello H, Ogunbiyi MO, Bossong MG, Freeman TP. The neuropsychopharmacology of cannabis: A review of human imaging studies. Pharmacol Ther 2018; 195:132-161. [PMID: 30347211 PMCID: PMC6416743 DOI: 10.1016/j.pharmthera.2018.10.006] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The laws governing cannabis are evolving worldwide and associated with changing patterns of use. The main psychoactive drug in cannabis is Δ9-tetrahydrocannabinol (THC), a partial agonist at the endocannabinoid CB1 receptor. Acutely, cannabis and THC produce a range of effects on several neurocognitive and pharmacological systems. These include effects on executive, emotional, reward and memory processing via direct interactions with the endocannabinoid system and indirect effects on the glutamatergic, GABAergic and dopaminergic systems. Cannabidiol, a non-intoxicating cannabinoid found in some forms of cannabis, may offset some of these acute effects. Heavy repeated cannabis use, particularly during adolescence, has been associated with adverse effects on these systems, which increase the risk of mental illnesses including addiction and psychosis. Here, we provide a comprehensive state of the art review on the acute and chronic neuropsychopharmacology of cannabis by synthesizing the available neuroimaging research in humans. We describe the effects of drug exposure during development, implications for understanding psychosis and cannabis use disorder, and methodological considerations. Greater understanding of the precise mechanisms underlying the effects of cannabis may also give rise to new treatment targets.
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Affiliation(s)
- Michael A P Bloomfield
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom; Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, Faculty of Brain Sciences, University College London, United Kingdom; Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, United Kingdom; NIHR University College London Hospitals Biomedical Research Centre, University College Hospital, London, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, United Kingdom.
| | - Chandni Hindocha
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom; Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, Faculty of Brain Sciences, University College London, United Kingdom; NIHR University College London Hospitals Biomedical Research Centre, University College Hospital, London, United Kingdom
| | - Sebastian F Green
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom
| | - Matthew B Wall
- Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, Faculty of Brain Sciences, University College London, United Kingdom; Centre for Neuropsychopharmacology, Division of Brain Sciences, Faculty of Medicine, Imperial College London, United Kingdom; Invicro UK, Hammersmith Hospital, London, United Kingdom
| | - Rachel Lees
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom; Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, Faculty of Brain Sciences, University College London, United Kingdom; Institute of Cognitive Neuroscience, Faculty of Brain Sciences, University College London, United Kingdom
| | - Katherine Petrilli
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom; Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, Faculty of Brain Sciences, University College London, United Kingdom; Institute of Cognitive Neuroscience, Faculty of Brain Sciences, University College London, United Kingdom
| | - Harry Costello
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom
| | - M Olabisi Ogunbiyi
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom
| | - Matthijs G Bossong
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands
| | - Tom P Freeman
- Translational Psychiatry Research Group, Research Department of Mental Health Neuroscience, Division of Psychiatry, Faculty of Brain Sciences, University College London, United Kingdom; Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, Faculty of Brain Sciences, University College London, United Kingdom; Department of Psychology, University of Bath, United Kingdom; National Addiction Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, United Kingdom
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22
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23
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Novick AM, Levandowski ML, Laumann LE, Philip NS, Price LH, Tyrka AR. The effects of early life stress on reward processing. J Psychiatr Res 2018; 101:80-103. [PMID: 29567510 PMCID: PMC5889741 DOI: 10.1016/j.jpsychires.2018.02.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/29/2018] [Accepted: 02/08/2018] [Indexed: 01/19/2023]
Abstract
Early life stress (ELS), in the form of childhood maltreatment, abuse, or neglect, increases the risk for psychiatric sequelae later in life. The neurobiology of response to early stress and of reward processing overlap substantially, leading to the prediction that reward processing may be a primary mediator of the effects of early life stress. We describe a growing body of literature investigating the effects of early life stressors on reward processing in animals and humans. Despite variation in the reviewed studies, an emerging pattern of results indicates that ELS results in deficits of ventral striatum-related functions of reward responsiveness and approach motivation, especially when the stressor is experienced in early in development. For stressors experienced later in the juvenile period and adolescence, the animal literature suggests an opposite effect, in which ELS results in increased hedonic drive. Future research in this area will help elucidate the transdiagnostic impact of early life stress, and therefore potentially identify and intervene with at-risk youth, prior to the emergence of clinical psychopathology.
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Affiliation(s)
- Andrew M. Novick
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Providence, RI, USA,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA,Corresponding author: Andrew M Novick, MD PhD, Butler Hospital, 345 Blackstone Blvd, Providence, RI 02906, USA,
| | - Mateus L. Levandowski
- Developmental Cognitive Neuroscience Lab (DCNL), Graduate Program in Psychology, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil
| | - Laura E. Laumann
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Providence, RI, USA
| | - Noah S. Philip
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Providence, RI, USA,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA,Center for Neurorestoration and Neurotechnology, Providence VA, Providence, RI, USA
| | - Lawrence H. Price
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Providence, RI, USA,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA
| | - Audrey R. Tyrka
- Mood Disorders Research Program and Laboratory for Clinical and Translational Neuroscience, Butler Hospital, Providence, RI, USA,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA
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24
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Moradi M, Saidijam M, Yadegarazari R, Jahangard L, Seifi M, Matinnia N, Ghaleiha A. Genes Encoding GABA-β and HT1D Receptors in Bipolar I (Manic Phase) Patients. Basic Clin Neurosci 2018; 9:129-134. [PMID: 29967672 PMCID: PMC6026092 DOI: 10.29252/nirp.bcn.9.2.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Introduction: According to the cumulative evidence, genes encoding GABA receptors inhibit neurotransmitters in CNS and are intricately involved in the pathogenesis of mood disorders. Based on this hypothesis, these genes may be expressed in bipolar patients. As a result, we evaluated the gene expressions of GABA-β3 and HT1D receptors to assess their associations with bipolar mood disorder. Methods: In this study, 22 patients with bipolar I disorder (single manic episode) and 22 healthy individuals were enrolled. All participants were older than 15 years and had referred to Farshchian Hospital, Hamadan, Iran. They were diagnosed based on DSM IV–TR criteria and young mania rating scale in order to determine the severity of mania by a psychiatrist as bipolar Type 1 disorder in manic episode. We evaluated the expression of GABA–β3 and HT1D receptor genes in peripheral blood mononuclear cells, using real-time RT-PCR analysis. Results: In our study, a reduction in the gene expression of GABA–β3 and HT1D receptors was observed in peripheral blood mononuclear cells of the patients with bipolar disorders compared to the healthy controls. Conclusion: The results of this study supports the hypothesis that the gene expression for serotonin and GABA receptors can be employed in elucidating the pathogenesis of bipolar disorders.
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Affiliation(s)
- Mohammadreza Moradi
- Molecular Medicine Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Massoud Saidijam
- Molecular Medicine Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Reza Yadegarazari
- Molecular Medicine Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Leila Jahangard
- Behavioral Disorders and Substance Abuse Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Seifi
- Molecular Medicine Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Nasrin Matinnia
- Department of Nursing, Faculty of Science, Hamadan Branch, Islamic Azad University, Hamadan, Iran
| | - Ali Ghaleiha
- Behavioral Disorders and Substance Abuse Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
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25
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Bossong MG, Wilson R, Appiah-Kusi E, McGuire P, Bhattacharyya S. Human Striatal Response to Reward Anticipation Linked to Hippocampal Glutamate Levels. Int J Neuropsychopharmacol 2018; 21:623-630. [PMID: 29444252 PMCID: PMC6030901 DOI: 10.1093/ijnp/pyy011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/09/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Dysfunctional reward processing is associated with a number of psychiatric disorders, such as addiction and schizophrenia. It is thought that reward is regulated mainly by dopamine transmission in the ventral striatum. Contemporary animal models suggest that striatal dopamine concentrations and associated behaviors are related to glutamatergic functioning in the ventral hippocampus. However, in humans the association between reward-related ventral striatal response and hippocampal glutamate levels is unclear. METHODS Nineteen healthy participants were studied using proton magnetic resonance spectroscopy to measure hippocampal glutamate levels, and functional magnetic resonance imaging to assess striatal activation and functional connectivity during performance of a monetary incentive delay task. RESULTS We found that ventral striatal activation related to reward processing was correlated with hippocampal glutamate levels. In addition, context-dependent functional coupling was demonstrated between the ventral striatum and both the lingual gyrus and hippocampus during reward anticipation. Elevated hippocampal glutamate levels were inversely related to context-dependent functional connectivity between the ventral striatum and the anterior hippocampus while anticipating reward. CONCLUSIONS These findings indicate that human striatal responses to reward are influenced by hippocampal glutamate levels. This may be relevant for psychiatric disorders associated with abnormal reward processing such as addiction and schizophrenia.
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Affiliation(s)
- Matthijs G Bossong
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, United Kingdom,Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands,Correspondence: Matthijs G. Bossong, PhD, Brain Center Rudolf Magnus, Department of Psychiatry, A01.126, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands ()
| | - Robin Wilson
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, United Kingdom
| | - Elizabeth Appiah-Kusi
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, United Kingdom
| | - Philip McGuire
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, United Kingdom
| | - Sagnik Bhattacharyya
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, United Kingdom
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26
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Freeman TP, Pope RA, Wall MB, Bisby JA, Luijten M, Hindocha C, Mokrysz C, Lawn W, Moss A, Bloomfield MAP, Morgan CJA, Nutt DJ, Curran HV. Cannabis Dampens the Effects of Music in Brain Regions Sensitive to Reward and Emotion. Int J Neuropsychopharmacol 2018; 21:21-32. [PMID: 29025134 PMCID: PMC5795345 DOI: 10.1093/ijnp/pyx082] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Despite the current shift towards permissive cannabis policies, few studies have investigated the pleasurable effects users seek. Here, we investigate the effects of cannabis on listening to music, a rewarding activity that frequently occurs in the context of recreational cannabis use. We additionally tested how these effects are influenced by cannabidiol, which may offset cannabis-related harms. METHODS Across 3 sessions, 16 cannabis users inhaled cannabis with cannabidiol, cannabis without cannabidiol, and placebo. We compared their response to music relative to control excerpts of scrambled sound during functional Magnetic Resonance Imaging within regions identified in a meta-analysis of music-evoked reward and emotion. All results were False Discovery Rate corrected (P<.05). RESULTS Compared with placebo, cannabis without cannabidiol dampened response to music in bilateral auditory cortex (right: P=.005, left: P=.008), right hippocampus/parahippocampal gyrus (P=.025), right amygdala (P=.025), and right ventral striatum (P=.033). Across all sessions, the effects of music in this ventral striatal region correlated with pleasure ratings (P=.002) and increased functional connectivity with auditory cortex (right: P< .001, left: P< .001), supporting its involvement in music reward. Functional connectivity between right ventral striatum and auditory cortex was increased by cannabidiol (right: P=.003, left: P=.030), and cannabis with cannabidiol did not differ from placebo on any functional Magnetic Resonance Imaging measures. Both types of cannabis increased ratings of wanting to listen to music (P<.002) and enhanced sound perception (P<.001). CONCLUSIONS Cannabis dampens the effects of music in brain regions sensitive to reward and emotion. These effects were offset by a key cannabis constituent, cannabidol.
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Affiliation(s)
- Tom P Freeman
- Clinical Psychopharmacology Unit, University College London, United Kingdom.,National Addiction Centre, King's College London, United Kingdom
| | - Rebecca A Pope
- Clinical Psychopharmacology Unit, University College London, United Kingdom
| | - Matthew B Wall
- Clinical Psychopharmacology Unit, University College London, United Kingdom.,Imanova Centre for Imaging Sciences, Imperial College London, Hammersmith Hospital, London, United Kingdom.,Neuropsychopharmacology Unit, Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - James A Bisby
- Institute of Cognitive Neuroscience, University College London, United Kingdom
| | - Maartje Luijten
- Behavioural Science Institute, Radboud University, Nijmegen, The Netherlands
| | - Chandni Hindocha
- Clinical Psychopharmacology Unit, University College London, United Kingdom
| | - Claire Mokrysz
- Clinical Psychopharmacology Unit, University College London, United Kingdom
| | - Will Lawn
- Clinical Psychopharmacology Unit, University College London, United Kingdom
| | - Abigail Moss
- Clinical Psychopharmacology Unit, University College London, United Kingdom
| | - Michael A P Bloomfield
- Psychiatric Imaging Group, Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom.,Division of Psychiatry, University College London, United Kingdom
| | - Celia J A Morgan
- Clinical Psychopharmacology Unit, University College London, United Kingdom.,Department of Psychology, University of Exeter, United Kingdom
| | - David J Nutt
- Neuropsychopharmacology Unit, Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - H Valerie Curran
- Clinical Psychopharmacology Unit, University College London, United Kingdom
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27
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Schauer GL, King BA, McAfee TA. Prevalence, correlates, and trends in tobacco use and cessation among current, former, and never adult marijuana users with a history of tobacco use, 2005-2014. Addict Behav 2017; 73:165-171. [PMID: 28525833 DOI: 10.1016/j.addbeh.2017.04.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/25/2017] [Accepted: 04/28/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Approximately 70% of current (past 30-day) adult marijuana users are current tobacco users, which may complicate tobacco cessation. We assessed prevalence and trends in tobacco cessation among adult ever tobacco users, by marijuana use status. METHODS Data came from the National Survey on Drug Use and Health, a cross-sectional, nationally representative, household survey of U.S. civilians. Analyses included current, former, and never marijuana users aged≥18 reporting ever tobacco use (cigarette, cigar, chew/snuff). We computed weighted estimates (2013-2014) of current tobacco use, recent tobacco cessation (quit 30days to 12months), and sustained tobacco cessation (quit>12months) and adjusted trends in tobacco use and cessation (2005-2014) by marijuana use status. We also assessed the association between marijuana and tobacco use status. RESULTS In 2013-2014, among current adult marijuana users reporting ever tobacco use, 69.1% were current tobacco users (vs. 38.5% of former marijuana users, p<0.0001, and 28.2% of never marijuana users, p<0.0001); 9.1% reported recent tobacco cessation (vs. 8.4% of former marijuana users, p<0.01, and 6.3% of never marijuana users, p<0.001), and 21.8% reported sustained tobacco cessation (vs. 53.1% of former marijuana users, p<0.01, and 65.5% of never marijuana users, p<0.0001). Between 2005 and 2014, current tobacco use declined and sustained tobacco cessation increased among all marijuana use groups. CONCLUSIONS Current marijuana users who ever used tobacco had double the prevalence (vs. never-marijuana users) of current tobacco use, and significantly lower sustained abstinence. Interventions addressing tobacco cessation in the context of use of marijuana and other substances may be warranted.
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Affiliation(s)
- Gillian L Schauer
- Department of Health Services, School of Public Health, University of Washington, United States; CDC Foundation, 600 Peachtree Street NE, Suite 1000, Atlanta, GA, 30308, United States.
| | - Brian A King
- Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, United States
| | - Timothy A McAfee
- Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, United States
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Murray RM, Englund A, Abi-Dargham A, Lewis DA, Di Forti M, Davies C, Sherif M, McGuire P, D'Souza DC. Cannabis-associated psychosis: Neural substrate and clinical impact. Neuropharmacology 2017. [PMID: 28634109 DOI: 10.1016/j.neuropharm.2017.06.018] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Prospective epidemiological studies have consistently demonstrated that cannabis use is associated with an increased subsequent risk of both psychotic symptoms and schizophrenia-like psychoses. Early onset of use, daily use of high-potency cannabis, and synthetic cannabinoids carry the greatest risk. The risk-increasing effects are not explained by shared genetic predisposition between schizophrenia and cannabis use. Experimental studies in healthy humans show that cannabis and its active ingredient, delta-9-tetrahydrocannabinol (THC), can produce transient, dose-dependent, psychotic symptoms, as well as an array of psychosis-relevant behavioral, cognitive and psychophysiological effects; the psychotogenic effects can be ameliorated by cannabidiol (CBD). Findings from structural imaging studies in cannabis users have been inconsistent but functional MRI studies have linked the psychotomimetic and cognitive effects of THC to activation in brain regions implicated in psychosis. Human PET studies have shown that acute administration of THC weakly releases dopamine in the striatum but that chronic users are characterised by low striatal dopamine. We are beginning to understand how cannabis use impacts on the endocannabinoid system but there is much still to learn about the biological mechanisms underlying how cannabis increases risk of psychosis. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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Affiliation(s)
- R M Murray
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK.
| | - A Englund
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK
| | - A Abi-Dargham
- Department of Psychiatry, School of Medicine, Stony Brook University, New York, USA
| | - D A Lewis
- Department of Psychiatry, University of Pittsburg, PA, USA
| | - M Di Forti
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK
| | - C Davies
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK
| | - M Sherif
- Department of Psychiatry, Yale University School of Medicine, CT, USA
| | - P McGuire
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK
| | - D C D'Souza
- Department of Psychiatry, Yale University School of Medicine, CT, USA
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29
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Allendorfer JB, Szaflarski JP. Neuroimaging studies towards understanding the central effects of pharmacological cannabis products on patients with epilepsy. Epilepsy Behav 2017; 70:349-354. [PMID: 28109780 DOI: 10.1016/j.yebeh.2016.11.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 11/11/2016] [Accepted: 11/14/2016] [Indexed: 02/04/2023]
Abstract
Recent interest for the use of cannabis-derived products as therapeutic agents in the treatment of epilepsies has necessitated a reevaluation of their effects on brain and behavior. Overall, prolonged cannabis use is thought to result in functional and structural brain alterations. These effects may be dependent on a number of factors: e.g., which phytocannabinoid is used (e.g., cannabidiol (CBD) vs. tetrahyrocannabinol (THC)), the frequency of use (occasional vs. heavy), and at what age (prenatal, childhood, adulthood) the use began. However, due to the fact that there are over seven hundred constituents that make up the Cannabis sativa plant, it is difficult to determine which compound or combination of compounds is responsible for specific effects when studying recreational users. Therefore, this review focuses only on the functional MRI studies investigating the effects of specific pharmacological preparations of cannabis compounds, specifically THC, tetrahydrocannabivarin (THCV), and CBD, on brain function in healthy individuals and persons with epilepsy with references to non-epilepsy studies only to underline the gaps in research that need to be filled before cannabis-derived products are considered for a wide use in the treatment of epilepsy. This article is part of a Special Issue entitled "Cannabinoids and Epilepsy".
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Affiliation(s)
- Jane B Allendorfer
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Jerzy P Szaflarski
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
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30
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Gubner NR, Thrul J, Kelly OA, Ramo DE. Young adults report increased pleasure from smoking cigarettes when drinking alcohol but not when using marijuana. ADDICTION RESEARCH & THEORY 2017; 26:71-76. [PMID: 29371859 PMCID: PMC5779098 DOI: 10.1080/16066359.2017.1311877] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Among young adults, cigarette smoking is strongly associated with alcohol and marijuana use. The present study compared self-reported co-use of cigarettes and alcohol versus cigarettes and marijuana among young adults using cross-sectional survey data. METHODS Participants were young adult cigarette smokers (age 18 to 25) who also reported past month alcohol or marijuana use enrolled in a randomized trial testing a smoking cessation intervention on Facebook. Participants self-reported extent of cigarette smoking under the influence of alcohol or marijuana and differences in perceived pleasure from cigarette smoking when drinking alcohol compared to using marijuana. RESULTS Among cigarette smokers who drank alcohol and used marijuana in the past month (n=200), a similar percentage of cigarettes were smoked under the influence of alcohol (42.4%±31.2%) and marijuana (43.1% ±30.0%). Among alcohol + marijuana users, perceived pleasure from smoking cigarettes was significantly greater when drinking alcohol versus when using marijuana (t(199)=7.05, p<0.001). There was, on average, an increase in perceived pleasure from smoking cigarettes when drinking alcohol, though perceived pleasure did not differ by binge drinking frequency. In contrast, there was on average no change in perceived pleasure from smoking cigarettes when using marijuana. Results from the cigarette smokers who used alcohol + marijuana were similar to cigarette smokers who only used alcohol (n=158) or only used marijuana (n=54). CONCLUSION Findings highlight greater perceived reward from smoking cigarettes when drinking alcohol compared to when using marijuana, informing smoking cessation interventions that target users of multiple substances.
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Affiliation(s)
- Noah R. Gubner
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, CA, USA
- Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco, CA, USA
| | - Johannes Thrul
- Center for Tobacco Control Research & Education, University of California, San Francisco, CA, USA
| | - Oona A. Kelly
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, CA, USA
| | - Danielle E. Ramo
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, CA, USA
- Center for Tobacco Control Research & Education, University of California, San Francisco, CA, USA
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31
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Martz ME, Trucco EM, Cope LM, Hardee JE, Jester JM, Zucker RA, Heitzeg MM. Association of Marijuana Use With Blunted Nucleus Accumbens Response to Reward Anticipation. JAMA Psychiatry 2016; 73:838-44. [PMID: 27384542 PMCID: PMC4972653 DOI: 10.1001/jamapsychiatry.2016.1161] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
IMPORTANCE Marijuana use may alter ventral striatal response to reward, which might heighten susceptibility to substance use disorder. Longitudinal research is needed to determine the effects of marijuana use on neural function involved in reward response. OBJECTIVE To determine whether marijuana use among young adults prospectively affects nucleus accumbens (NAcc) activation during reward anticipation. DESIGN, SETTING, AND PARTICIPANTS One hundred eight young adults were recruited from the Michigan Longitudinal Study, an ongoing study of youth at high risk for substance use disorder and a contrast sample of control families. Participants underwent 3 consecutive functional magnetic resonance imaging scans at approximate ages of 20 (time 1), 22 (time 2), and 24 (time 3) years. Self-report data on marijuana and other drug use occasions were collected annually since age 11 years. MAIN OUTCOMES AND MEASURES Cross-lagged models were used to test the association of marijuana use with neural response in the NAcc to reward anticipation during a monetary incentive delay task controlling for sex, age, other substance use, and family history of substance use disorder. RESULTS Of 108 participants, 39 (36.1%) were female and mean (SD) age at baseline was 20.1 (1.4) years. Greater marijuana use was associated with later blunted activation in the NAcc during reward anticipation (time 1 to time 2: β = -0.26, P = .04; time 2 to time 3: β = -0.25, P = .01). When the cross-lagged model was tested with the inclusion of previous and concurrent cigarette use, the effect of marijuana use from time 2 to time 3 remained significant (β = -0.29; P = .005) and the effect of cigarette use was nonsignificant. CONCLUSIONS AND RELEVANCE The findings of this study indicate that marijuana use is associated with decreased neural response in the NAcc during the anticipation of nondrug rewards. Over time, marijuana use may alter anticipatory reward processing in the NAcc, which may increase the risk for continued drug use and later addiction.
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Affiliation(s)
- Meghan E. Martz
- Department of Psychiatry and Addiction Research Center, University of Michigan 4250 Plymouth Rd., Ann Arbor, MI 48109, USA,Department of Psychology, University of Michigan, 530 Church St., Ann Arbor, MI 48108, USA
| | - Elisa M. Trucco
- Department of Psychiatry and Addiction Research Center, University of Michigan 4250 Plymouth Rd., Ann Arbor, MI 48109, USA,Department of Psychology, Center for Children and Families, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
| | - Lora M. Cope
- Department of Psychiatry and Addiction Research Center, University of Michigan 4250 Plymouth Rd., Ann Arbor, MI 48109, USA
| | - Jillian E. Hardee
- Department of Psychiatry and Addiction Research Center, University of Michigan 4250 Plymouth Rd., Ann Arbor, MI 48109, USA
| | - Jennifer M. Jester
- Department of Psychiatry and Addiction Research Center, University of Michigan 4250 Plymouth Rd., Ann Arbor, MI 48109, USA
| | - Robert A. Zucker
- Department of Psychiatry and Addiction Research Center, University of Michigan 4250 Plymouth Rd., Ann Arbor, MI 48109, USA,Department of Psychology, University of Michigan, 530 Church St., Ann Arbor, MI 48108, USA
| | - Mary M. Heitzeg
- Department of Psychiatry and Addiction Research Center, University of Michigan 4250 Plymouth Rd., Ann Arbor, MI 48109, USA
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Subramaniam P, McGlade E, Yurgelun-Todd D. Comorbid Cannabis and Tobacco Use in Adolescents and Adults. CURRENT ADDICTION REPORTS 2016; 3:182-188. [PMID: 27175326 DOI: 10.1007/s40429-016-0101-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The prevalence of comorbid cannabis and tobacco use has been increasing among adolescents and adults and has been shown to be associated with a range of changes or deficits in physical, psychological and behavioral outcomes. Moreover, comorbid use has been shown to have a differential effect on the structure and function of the brain, especially as it relates to the reward circuitry and learning and memory. This interaction might be mediated by the involvement of the endocannabinoid system and alterations in dopamine signaling in regions associated with reward and cognitive functioning. While current findings demonstrate a differential effect of comorbid use on neurobiological and behavioral correlates compared with single substance use, additional studies are needed controlling for potential psychiatric comorbidities, age of onset of use and use of other substances. Understanding the neurobiological mechanisms associated with comorbid cannabis and tobacco use will be important in developing successful treatment outcomes in the future.
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Affiliation(s)
- Punitha Subramaniam
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA; Diagnostic Neuroimaging, University of Utah, Salt Lake City, UT USA
| | - Erin McGlade
- Diagnostic Neuroimaging, University of Utah, Salt Lake City, UT USA; Department of Psychiatry, University of Utah, Salt Lake City, UT; George E. Whalen Department of Veterans Affairs Medical Center, VA VISN 19 Mental Illness Research, Education and Clinical Center (MIRREC), Salt Lake City, UT, USA
| | - Deborah Yurgelun-Todd
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA; Diagnostic Neuroimaging, University of Utah, Salt Lake City, UT USA; Department of Psychiatry, University of Utah, Salt Lake City, UT; George E. Whalen Department of Veterans Affairs Medical Center, VA VISN 19 Mental Illness Research, Education and Clinical Center (MIRREC), Salt Lake City, UT, USA
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Sherif M, Radhakrishnan R, D'Souza DC, Ranganathan M. Human Laboratory Studies on Cannabinoids and Psychosis. Biol Psychiatry 2016; 79:526-38. [PMID: 26970363 DOI: 10.1016/j.biopsych.2016.01.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 01/14/2016] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
Abstract
Some of the most compelling evidence supporting an association between cannabinoid agonists and psychosis comes from controlled laboratory studies in humans. Randomized, double-blind, placebo-controlled, crossover laboratory studies demonstrate that cannabinoid agonists, including phytocannabinoids and synthetic cannabinoids, produce a wide range of positive, negative, and cognitive symptoms and psychophysiologic deficits in healthy human subjects that resemble the phenomenology of schizophrenia. These effects are time locked to drug administration, are dose related, and are transient and rarely necessitate intervention. The magnitude of effects is similar to the effects of ketamine but qualitatively distinct from other psychotomimetic drugs, including ketamine, amphetamine, and salvinorin A. Cannabinoid agonists have also been shown to transiently exacerbate symptoms in individuals with schizophrenia in laboratory studies. Patients with schizophrenia are more vulnerable than healthy control subjects to the acute behavioral and cognitive effects of cannabinoid agonists and experience transient exacerbation of symptoms despite treatment with antipsychotic medications. Furthermore, laboratory studies have failed to demonstrate any "beneficial" effects of cannabinoid agonists in individuals with schizophrenia-challenging the cannabis self-medication hypothesis. Emerging evidence suggests that polymorphisms of several genes related to dopamine metabolism (e.g., COMT, DAT1, and AKT1) may moderate the effects of cannabinoid agonists in laboratory studies. Cannabinoid agonists induce dopamine release, although the magnitude of release does not appear to be commensurate to the magnitude and spectrum of their acute psychotomimetic effects. Interactions between the endocannabinoid, gamma-aminobutyric acid, and glutamate systems and their individual and interactive effects on neural oscillations provide a plausible mechanism underlying the psychotomimetic effects of cannabinoids.
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Affiliation(s)
- Mohamed Sherif
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, Connecticut; Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut
| | - Rajiv Radhakrishnan
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, Connecticut; Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut
| | - Deepak Cyril D'Souza
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, Connecticut; Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut
| | - Mohini Ranganathan
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, Connecticut; Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut.
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34
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Balodis IM, Potenza MN. Anticipatory reward processing in addicted populations: a focus on the monetary incentive delay task. Biol Psychiatry 2015; 77:434-44. [PMID: 25481621 PMCID: PMC4315733 DOI: 10.1016/j.biopsych.2014.08.020] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 08/12/2014] [Accepted: 08/26/2014] [Indexed: 11/26/2022]
Abstract
Advances in brain imaging techniques have allowed neurobiological research to temporally analyze signals coding for the anticipation of reward. In addicted populations, both hyporesponsiveness and hyperresponsiveness of brain regions (e.g., ventral striatum) implicated in drug effects and reward system processing have been reported during anticipation of generalized reward. We discuss the current state of knowledge of reward processing in addictive disorders from a widely used and validated task: the monetary incentive delay task. Only studies applying the monetary incentive delay task in addicted and at-risk adult populations are reviewed, with a focus on anticipatory processing and striatal regions activated during task performance as well as the relationship of these regions with individual difference (e.g., impulsivity) and treatment outcome variables. We further review drug influences in challenge studies as a means to examine acute influences on reward processing in abstinent, recreationally using, and addicted populations. Generalized reward processing in addicted and at-risk populations is often characterized by divergent anticipatory signaling in the ventral striatum. Although methodologic and task variations may underlie some discrepant findings, anticipatory signaling in the ventral striatum may also be influenced by smoking status, drug metabolites, and treatment status in addicted populations. Divergent results across abstinent, recreationally using, and addicted populations demonstrate complexities in interpreting findings. Future studies would benefit from focusing on characterizing how impulsivity and other addiction-related features relate to anticipatory striatal signaling over time. Additionally, identifying how anticipatory signals recover or adjust after protracted abstinence will be important in understanding recovery processes.
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Affiliation(s)
- Iris M. Balodis
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Corresponding Author: Iris M. Balodis, PhD, Yale University School of Medicine, 1 Church Street, Rm 731, New Haven, CT 06519, Tel: 203-737-2668,
| | - Marc N. Potenza
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Department of Neurobiology, Yale University School of Medicine, New Haven, CT, USA,Child Study Center, Yale University School of Medicine, New Haven, CT, USA
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Bossong MG, Jansma JM, Bhattacharyya S, Ramsey NF. Role of the endocannabinoid system in brain functions relevant for schizophrenia: an overview of human challenge studies with cannabis or ∆9-tetrahydrocannabinol (THC). Prog Neuropsychopharmacol Biol Psychiatry 2014; 52:53-69. [PMID: 24380726 DOI: 10.1016/j.pnpbp.2013.11.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 10/16/2013] [Accepted: 11/25/2013] [Indexed: 12/30/2022]
Abstract
Accumulating evidence suggests involvement of the endocannabinoid system in the pathophysiology of schizophrenia, which signifies a potential application for this system in the treatment of this disorder. However, before new research can focus on potential treatments that work by manipulating the endocannabinoid system, it needs to be elucidated how this system is involved in symptoms of schizophrenia. Here we review human studies that investigated acute effects of cannabis or ∆9-tetrahydrocannabinol (THC) on brain functions that are implicated in schizophrenia. Results suggest that the impact of THC administration depends on the difficulty of the task performed. Impaired performance of cognitive paradigms is reported on more challenging tasks, which is associated with both activity deficits in temporal and prefrontal areas and a failure to deactivate regions of the default mode network. Comparable reductions in prefrontal activity and impairments in deactivation of the default mode network are seen in patients during performance of cognitive paradigms. Normal performance levels after THC administration demonstrated for less demanding tasks are shown to be related to either increased neural effort in task-specific regions ('neurophysiological inefficiency'), or recruitment of alternative brain areas, which suggests a change in strategy to meet cognitive demands. Particularly a pattern of performance and brain activity corresponding with an inefficient working memory system is consistently demonstrated in patients. These similarities in brain function between intoxicated healthy volunteers and schizophrenia patients provide an argument for a role of the endocannabinoid system in symptoms of schizophrenia, and further emphasize this system as a potential novel target for treatment of these symptoms.
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Affiliation(s)
- Matthijs G Bossong
- Institute of Psychiatry, Department of Psychosis Studies, King's College London, 16 De Crespigny Park, London SE5 8AF, United Kingdom.
| | - J Martijn Jansma
- Rudolf Magnus Institute of Neuroscience, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Sagnik Bhattacharyya
- Institute of Psychiatry, Department of Psychosis Studies, King's College London, 16 De Crespigny Park, London SE5 8AF, United Kingdom
| | - Nick F Ramsey
- Rudolf Magnus Institute of Neuroscience, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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