Search

Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background and Aims: Despite high rates of relapse after treatment for drug use, to our knowledge there is no systematic literature identifying psychological factors that predict risk of relapse to drug use (excluding alcohol or tobacco). Our aim was to identify psychological factors that predict risk of relapse to drug use after enrollment in drug use treatment. The identification of such factors can support treatment planning and relapse prevention., Methods: We searched for peer-reviewed articles published between 2000 and 2023 in PsycINFO, PsycArticles, Web of Science, and PubMed. The inclusion criteria were: peer-reviewed publications, quantitative studies, in English, adult samples, with a prospective design, and analyses of minimum one psychological factor as predictor of relapse to drug use. All authors were involved in abstract and full-text screening, and in assessing risk of bias. The findings are presented in a narrative synthesis and tables are organized by type of drug., Results: Of 2226 publications initially identified, 45 were eligible. Twenty-three focused on predicting relapse to stimulants, 15 to opioids, and 7 to unspecified drugs. Substance use at baseline was an important factor predicting risk of relapse to opioids, and possibly stimulants. There was an indication that craving and attention problems potentially predict relapse to use of some drugs. Mental health factors (e.g., psychiatric diagnosis) did not predict relapse. Several psychological factors (e.g., cognition, emotion, personality, motivation) were scarcely examined. Over half of the studies had moderate to high risk of bias., Conclusions: Based on the 45 studies, few psychological factors predicted risk of relapse to drug use. Higher comparability between studies and more rigorous methodology are necessary in order to derive more precise recommendations that inform and improve clinical practice., Pre-Registration: PROSPERO, CRD42020182839., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In Europe, concentrations of ∆ 9 -tetrahydrocannabinol (THC) in cannabis resin (also known as hash) have risen markedly in the past decade, potentially increasing risks of mental health disorders. Current approaches to international drug monitoring cannot distinguish between different types of cannabis resin which may have contrasting health effects due to THC and cannabidiol (CBD) content. Here, we compared concentrations of THC and CBD in different types of cannabis resin collected in Europe (either Moroccan-type, or Dutch-type). We then tested the ability of machine learning algorithms to classify the type of cannabis resin (either Moroccan-type, or Dutch-type) using routinely collected monitoring data on THC and CBD. Finally, we applied the optimal algorithm to new samples collected in countries where the type of cannabis resin was unknown, the UK and Denmark. Results showed that overall, Dutch-type samples had higher THC (Hedges' g = 2.39) and lower CBD (Hedges' g = 0.81) than Moroccan-type samples. A Support Vector Machine algorithm achieved classification accuracy exceeding 95%, with little variation in this estimate, good interpretability, and plausibility. It made contrasting predictions about the type of cannabis resin collected in the UK (94% Moroccan-type; 6% Dutch-type) and Denmark (36% Moroccan-type; 64% Dutch-type). In conclusion, we provide proof-of-concept evidence for the potential of machine learning to inform international drug monitoring. Our findings should not be interpreted as objective confirmatory evidence but suggest that Dutch-type cannabis resin has higher THC concentrations than Moroccan-type cannabis resin, which may contribute to variation in drug markets and health outcomes for people who use cannabis in Europe., (© 2024. The Author(s).)

Drinking is closely intertwined with social life among many adolescents, particularly in Europe. Group-based interventions, such as group-based motivational interviewing (group MI), have shown the capacity to prevent and reduce hazardous drinking and related problems among adolescents, but few examinations have been conducted in a European high school setting. This study examines the preliminary outcomes of a pilot group MI intervention among Danish adolescents. High school students (ages 15-18 years) were randomly allocated to two 1-h group MI sessions delivered in a school setting ( N  = 65) or an assessment only control condition ( N  = 67). Data were collected in August and November 2020 using online self-administrated questionnaires regarding the acceptability of the intervention and past month alcohol use. The pilot group MI intervention showed high feasibility and acceptability in this setting and with this age group. Group MI adolescents significantly reduced peak drinks per drinking day compared to assessment only adolescents (-2.7 drinks, p  < 0.05). Results are discussed in relation to the metrics being evaluated during COVID-19 lockdown, including increased social restrictions at follow-up compared to baseline. Group MI shows promise for reducing hazardous alcohol use among Danish adolescents. In addition, the findings indicate the importance of building on and extending this work in future larger, better-powered randomized controlled trials., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Vallentin-Holbech, Karsberg, Nielsen, Feldstein Ewing and Rømer Thomsen.)

Objective: The Timeline Followback (TLFB) is a widely used and well-validated interview-based tool for assessing patterns of recent health risk behavior. There is some evidence of the validity of the TLFB as a self-administered online tool for assessing alcohol use, but further research is needed to establish its validity in younger populations and populations outside the United States. Further, it is unknown how self-administered online TLFB formats compare to more timesaving and commonly used single-item alcohol questions. The primary aim of the current study was to validate a new online, self-administered TLFB for alcohol use against the TLFB interview in a sample of European (Danish) adolescents aged 16-18 years ( N = 30)., Methods: Participants completed a TLFB telephone interview, a self-administered online version of the TLFB, and single-item alcohol questions. Assessments were administered using a within-subject, counter-balanced design. Estimates of number of drinking days, binge-drinking days, maximum drinks consumed on one occasion, total drinks, and drinks per drinking day were compared across metrics., Results: All correlations between the drinking outcomes assessed via the TLFB interview and the TLFB online were positive, and statistically significant ( r s s = 0.86-0.94, p < 0.01). Wilcoxon signed-rank tests showed no significant differences between the TLFB interview and the TLFB online on drinking days, binge drinking days, max drinks, and total drinks. Participants reported drinking significantly more drinks per drinking day on the TLFB online (M = 4.66) compared to on the TLFB interview (M = 4.12; p = 0.009)., Conclusion: Overall, the results support the validity of the online, self-administered TLFB in a sample of European (Danish) adolescents., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Hareskov Jensen, Vallentin-Holbech, Dash, Feldstein Ewing and Rømer Thomsen.)

Background: Adolescent hazardous alcohol use is prevalent and has serious short- and long-term consequences. The trial 'Our Choice' examines efficacy, feasibility and acceptability of prevention interventions targeting school, parent, and student levels at Danish high schools. We hypothesize that students in a structural intervention (school and parent levels) reduce hazardous alcohol use and related health behaviors compared to students in an assessment only control group 12 months post baseline; and that adding group-based Motivational Interviewing (group MI) yields further improvements. The study examines the efficacy of interventions targeting multiple levels with the aim of providing novel insights into prevention of adolescent hazardous alcohol use and related health outcomes., Method: The study employs a parallel group cluster randomized controlled trial design with three conditions: (1) structural condition targeting school and parent levels, (2) structural condition combined with group MI which also targets the student level, and (3) assessment-only control condition. A participatory approach is used to adapt and develop interventions. Sixteen high schools in Denmark and about N = 3100 first-year students (15-18 years) enrolled in high school in August 2023 will be recruited. Data will be collected via online questionnaires pre-interventions (baseline), 2, 6, 9 and 12 month post baseline and analyzed with generalized linear mixed models. The primary outcome is past month high intensity drinking; secondary outcomes are alcohol use, alcohol-related consequences, well-being, tobacco, and illegal substance use. Feasibility and acceptability will be assessed via surveys (students) and interviews (high school staff) to inform future implementation., Discussion: 'Our Choice' is the first trial to compare the efficacy of a structural intervention targeting school- and parent levels to an intervention targeting these levels and the student level via group MI - on hazardous drinking and related health outcomes among students. Preventing and reducing hazardous alcohol use during adolescence is crucial due to the short- and long-term negative consequences. The tested interventions can be implemented at low cost. The study has significant implications for adolescent health and well-being and has potential to inform evidence-based decisions on alcohol prevention policy, education, and health professions., Trial Registration Number: The trial was retrospectively registered at ClinicalTrials.gov on August 24th, 2023., Trial Registration Number: ID NCT06018389., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Cannabis use peaks during adolescence and emerging adulthood, and cannabis use disorder (CUD) is associated with a wide range of adverse outcomes. This is particularly pertinent in youth, because the developing brain may be more vulnerable to adverse effects of frequent cannabis use. Combining evidence-based psychosocial interventions with safe and effective pharmacotherapy is a potential avenue to improve youth outcomes, but we lack approved CUD pharmacotherapies. Here, we review new potential avenues for helping youth with CUD, with a particular focus on cannabinoid-based treatments. Evidence from placebo-controlled RCTs suggests synthetic delta-9-tetrahydrocannabinol (THC) decreases withdrawal symptoms, but not cannabis use, in adults with daily cannabis use/CUD, while findings regarding formulations containing THC combined with cannabidiol (CBD) are mixed. Preliminary evidence from two placebo-controlled RCTs in adults with CUD suggests that both Fatty Acid Amide Hydrolase inhibitors and CBD can reduce cannabis use. However, larger trials are needed to strengthen the evidence. Findings from adults point to cannabinoid-based treatments as a potential strategy that should be examined in youth with CUD., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: There is consistent evidence that community and clinical samples of individuals with an alcohol use disorder (AUD) have attentional biases toward alcohol cues. The alcohol attentional control training program (AACTP) has shown promise for retraining these biases and decreasing alcohol consumption in community samples of excessive drinkers. However, there is a lack of evidence regarding the effectiveness of ACTP in clinical AUD samples. The main aim of the present study is to investigate whether primary pharmacological and psychological, evidence-based alcohol treatment can be enhanced by the addition of a gamified AACTP smartphone application for patients with an AUD. Design and Methods: The study will be implemented as a randomized controlled trial. A total of 317 consecutively enrolled patients with AUD will be recruited from alcohol outpatient clinics in Denmark. Patients will be randomized to one of three groups upon initiation of primary alcohol treatment: Group A: a gamified AACTP smartphone application + treatment as usual (TAU); Group B: a gamified AACTP sham-control application + TAU; or Group C: only TAU. Treatment outcomes will be assessed at baseline, post-treatment, and at 3- and 6-month follow-ups. Repeated measures MANOVA will be used to compare the trajectories of the groups over time on alcohol attentional bias, alcohol craving, and drinking reductions. It is hypothesized that Group A will achieve better treatment outcomes than either Group B or Group C. Perspectives: Because attentional bias for alcohol cues is proportional to the amount of alcohol consumed, and these biases are not addressed within current evidence-based treatment programs, this study is expected to provide new evidence regarding the effectiveness of the gamified AACTP in a clinical population. Furthermore, due to promising results found using AACTP in community samples of excessive drinkers, there is a high probability that the AACTP treatment in this study will also be effective, thereby allowing AACTP to be readily implemented in clinical settings. Finally, we expect that this study will increase the effectiveness of evidence-based AUD treatment and introduce a new, low-cost gamified treatment targeting patients with an AUD. Overall, this study is likely to have an impact at the scientific, clinical, and societal levels. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT05102942?term=NCT05102942&draw=2&rank=1, identifier: NCT05102942., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Mellentin, Cox, Fadardi, Martinussen, Mistarz, Skøt, Rømer Thomsen, Mathiasen, Lichtenstein and Nielsen.)

Background: The use of cannabis as medicine (CaM) both prescribed and non-prescribed has increased markedly in the last decade, mirrored in a global shift in cannabis policy towards a more permissive stance. There is some evidence that cannabis functions as a substitute for prescription drugs, particularly opioids; however, more knowledge is needed on the motives of substitution users, their patterns of use, and perceived effects of substitution use., Aims: To explore who substitutes prescription drugs with cannabis, the type of prescription drugs substituted and the type of cannabis used, and the impact that substitution with cannabis has on prescription drug use as well as the motives for substitution in terms of experienced effects and side effects., Methods: A self-selected convenience sample was recruited through social media, public media, and patient organizations to take part in an anonymous online survey. Inclusion criteria were 18 years or older and use of cannabis (prescribed or non-prescribed) with a medical purpose., Results: The final sample included 2.841 respondents of which the majority (91%) used non-prescribed cannabis, and more than half (54.6%) had used CaM with the purpose of replacing a prescribed drug. Compared to non-substitution users, substitution users were more likely to be women and to use CaM in the treatment of chronic pain and other somatic conditions. Pain medication (67.2%), antidepressants (24.5%), and arthritis medication (20.7%) were the most common types of drugs replaced with CaM. Among substitution users, 38.1% reported termination of prescription drug use, and 45.9% a substantial decrease in prescription drug use. The most frequent type of cannabis used as a substitute was CBD-oil (65.2%), followed by 'hash, pot or skunk' (36.6%). More than half (65.8%) found CaM much more effective compared to prescription drugs, and 85.5% that the side effects associated with prescription drug use were much worse compared to use of CaM., Conclusion: CaM is frequently used as a substitute for prescription drugs, particularly opioids. More research is needed on the long-term consequences of use of CaM, including the impact from low and high THC cannabis products on specific somatic and mental health conditions., (© 2021. The Author(s).)

The electrophysiology of the paralimbic network ("default mode") for self-awareness has drawn much attention in the past couple of decades. In contrast, knowledge of the molecular organization of conscious experience has only lately come into focus. We here review newer data on dopaminergic control of awareness in humans, particularly in self-awareness. These results implicate mainly dopaminergic neurotransmission and the control of GABAergic function directly in the paralimbic network. The findings are important for understanding addiction, developmental disorders, and dysfunctional consciousness., (Copyright © 2020 Lou, Rømer Thomsen and Changeux.)

Globally, recent studies report increases in Δ-9-tetrahydrocannabinol (THC) concentration in seized samples of cannabis for human consumption. This is important, because use of cannabis with a high concentration of THC has been linked to a number of adverse health outcomes. The objective of this study was to assess recent changes in the composition of seized cannabis resin in Denmark by (a) examining THC concentration in samples from Danish forensic laboratories from 2000 to 2017 ( N = 430) and (b) examining cannabidiol (CBD) concentration and the THC:CBD concentration ratio in samples from the forensic laboratory in Western Denmark from 2008 to 2017 ( N = 147). Cannabis resin samples were analyzed using a gas chromatographic analysis with flame ionization detection quantifying the total THC and CBD concentration. Results showed that the THC concentration increased 3-fold from 2000 (mean: 8.3%) to 2017 (mean: 25.3%). Significant increases occurred in all areas of Denmark. After 2011, we found a dramatic increase in cannabis resin samples with high THC concentration and the near disappearance of cannabis resin samples with medium- and low THC concentration. Furthermore, the THC:CBD concentration ratio increased significantly from 1.4 in 2008 to 4.4 in 2017. Whereas THC concentration increased, CBD concentration remained stable at ∼6%. In conclusion, the THC concentration of cannabis resin, and THC:CBD concentration ratio, have increased dramatically in Denmark, potentially leading to higher risk of harm to users. Policymakers, treatment professionals, and educators should be aware of this change. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Rationale: Identifying the predictors of relapse in detoxified alcohol-dependent patients is crucial for effective surveillance procedures and the optimization of treatment. Physiological measures such as functional MRI activity and heart rate variability have been shown as potential markers of relapse prediction., Objectives: Our aim was to assess differential pupillary reactions to alcohol-related cues as an objective physiological candidate predictor of relapse., Methods: We examined the relationship between cue-elicited pupillary reactions to alcohol stimuli and luminance-controlled neutral stimuli in 21 detoxified alcohol-dependent patients and subsequent relapse outcome at a 4-month follow-up., Results: Differential pupillary dilation to alcohol stimuli as compared to neutral stimuli at 150 to 250 ms after stimulus onset substantially improved the model prediction of relapse outcome (additional 27% of variance) beyond that achieved from five standardized questionnaires on alcohol craving, alcohol use, problematic use severity, depressive tendencies, and duration of abstinence (47% of variance). In contrast, alcohol craving did not improve relapse model prediction., Conclusions: This pilot study shows that alcohol-dependent patients with greater pupillary dilation to alcohol stimuli are more vulnerable to relapse, and that pupillometry presents as an important tool for addiction science.

Although adolescents are developmentally distinct from adults, they often receive addiction treatment based on adult models. This is problematic because adolescents face significantly different conditions in addiction treatment, including distinct basic biological and neurodevelopmental stages, unique sociodevelopmental concerns, distinctive addiction trajectories, and, in turn, disparate treatment goals and outcomes. In sum, it can be difficult for even savvy clinicians to know how to approach addiction treatment with this important age group. In an effort to help clinicians and researchers consider substance use via a neurodevelopmental lens, we approached this review with 4 goals: (i) characterize the prevalence, and related health and safety implications of substance use within this age group; (ii) identify the nature of the adolescent brain, including characteristic features of this phase of neurodevelopment relevant to adolescent substance use treatment; (iii) provide an overview of current adolescent addiction interventions and avenues to improve clinical treatment and clinical research efforts for adolescents; and (iv) examine the intersection between the nature of the developing brain and adolescent substance use, and utilize that information to inform alternative routes and directions for substance use treatment in this critical age group. This review concludes by offering a novel neurodevelopmental model and framework to examine substance use interventions, along with a series of recommendations to optimize adolescent substance use treatment and clinical research., (© 2019 by the Research Society on Alcoholism.)

Introduction: We have previously shown that an interaction between medial prefrontal and parietal cortices is instrumental in promoting self-awareness via synchronizing oscillations in the gamma range. The synchronization of these oscillations is modulated by dopamine release. Given that such oscillations result from intermittent GABA stimulation of pyramidal cells, it is of interest to determine whether the dopaminergic system regulates GABA release directly in cortical paralimbic regions. Here, we test the hypothesis that the regulation of the GABA-ergic system by the dopaminergic system becomes attenuated in problem gamblers resulting in addictive behaviors and impaired self-awareness., Methods: [ 11 C]Ro15-4513 PET, a marker of benzodiazepine α1/α5 receptor availability in the GABA receptor complex, was used to detect changes in synaptic GABA levels after oral doses of 100mg L-dopa in a double-blind controlled study of male problem gamblers (N = 10) and age-matched healthy male controls (N = 10)., Results: The mean reduction of cortical gray matter GABA/BDZ receptor availability induced by L-dopa was significantly attenuated in the problem gambling group compared to the healthy control group (p = 0.0377)., Conclusions: Our findings demonstrate that: (a) Exogenous dopamine can induce synaptic GABA release in healthy controls. (b) This release is attenuated in frontal cortical areas of males suffering from problem gambling, possibly contributing to their loss of inhibitory control. This suggests that dysfunctional dopamine regulation of GABA release may contribute to problem gambling and gambling disorder., (© 2019 Aarhus University Hospital, Nuclear Medicine and PET. Brain and Behavior published by Wiley Periodicals, Inc.)

Background: Controlling drinking behaviour requires the ability to block out distracting alcohol cues in situations in which drinking is inappropriate or harmful. However, at present few studies have investigated whether distraction and response inhibition to contextual alcohol cues are related to alcohol use in adolescents and young adults. We aimed to investigate whether tendencies towards distraction and failures of response inhibition in the presence of contextual alcohol cues, and alcohol craving were associated with higher levels of alcohol consumption, beyond what could be explained by demographic variables., Methods: To test this, 108 participants (Mean age = 21.7, range = 16-27), whom were both drinkers and non-drinkers performed a modified Go/NoGo task tailored to measure distraction and response inhibition in the presence of alcohol cues relative to neutral stimuli. Alcohol craving was assessed using a visual analogue scale of craving for different types of alcohol cues. Levels of alcohol use and problematic alcohol use were assessed using a self-report measure of number of drinking days in the previous month and the Alcohol Use Disorders Identification Test. Data were analysed using sequential multiple regression using a zero-inflated negative binomial distribution model., Results: Drinking days correlated with distraction but not response inhibition to contextual alcohol cues. Sequential regression analyses revealed that the inclusion of distraction bias accounted for 11% additional variance (significant) in alcohol use, in addition to that explained by demographics alone (17%). Craving for alcohol explained an additional 30% variance (significant) in alcohol use., Conclusions: The results reported here support the idea that both biased distraction towards alcohol cues and alcohol craving are associated with preceding drinking days, but not necessarily drinking status. Further studies are warranted that address whether cognitive distraction to alcohol-related cues cause or is an effect of alcohol use among youth.

Background and aims Impulsivity is a risk factor for addictive behaviors. The UPPS-P impulsivity model has been associated with substance addiction and gambling disorder, but its role in other non-substance addiction-related behaviors is less understood. We sought to examine associations between UPPS-P impulsivity traits and indicators of multiple substance and non-substance addiction-related behaviors in youth with varying involvement in these behaviors. Methods Participants (N = 109, aged 16-26 years, 69% males) were selected from a national survey based on their level of externalizing problems to achieve a broad distribution of involvement in addiction-related behaviors. Participants completed the UPPS-P Questionnaire and standardized questionnaires assessing problematic use of substances (alcohol, cannabis, and other drugs) and non-substances (Internet gaming, pornography, and food). Regression analyses were used to assess associations between impulsivity traits and indicators of addiction-related behaviors. Results The UPPS-P model was positively associated with indicators of all addiction-related behaviors except problematic Internet gaming. In the fully adjusted models, sensation seeking and lack of perseverance were associated with problematic use of alcohol, urgency was associated with problematic use of cannabis, and lack of perseverance was associated with problematic use of other drugs than cannabis. Furthermore, urgency and lack of perseverance were associated with binge eating and lack of perseverance was associated with problematic use of pornography. Discussion and conclusions We emphasize the role of trait impulsivity across multiple addiction-related behaviors. Our findings in at-risk youth highlight urgency and lack of perseverance as potential predictors for the development of addictions and as potential preventative therapeutic targets.

Background: Patients with schizophrenia and comorbid drug use disorders (DUD) have a severe course of illness. Despite strong evidence that drug use can exacerbate psychotic symptoms, we have limited knowledge of how specific drugs may increase risk of schizophrenia readmission in this group. This study aimed to assess drug-related predictors of readmission for schizophrenia among a national cohort of patients with a history of schizophrenia admitted to DUD treatment., Methods: A record-linkage study was used to assess drug-related factors associated with readmission to mental health treatment for schizophrenia, using a consecutive cohort of 634 patients admitted to DUD treatment between 2000 and 2006 in Danish treatment services and tracked until February 2013 or death, controlling for baseline psychiatric treatment variables., Results: The majority of patients were males (79.8%) and the mean age was 34.7years. Of all patients, 78.7% were readmitted for schizophrenia during follow-up, and 6.8% died without having been readmitted. We found a robust association between use of amphetamine at baseline and elevated risk of readmission, a less robust association between use of cannabis and elevated risk of readmission, and no association with cocaine, opioids, alcohol, benzodiazepines, and MDMA. Furthermore, one or more psychiatric inpatients visit in the year prior to DUD admission was robustly associated with elevated risk of schizophrenia readmission., Conclusions: Use of amphetamine and cannabis are risk markers for schizophrenia readmission among patients with a history of schizophrenia and DUD. Psychiatric history is a predictor of schizophrenia readmission in this patient group., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Problems related to the capacity to successfully engage response inhibition are considered a risk factor for the development of substance use disorders (SUDs), but the evidence has been predominantly cross-sectional. In this commentary, we argue that recent longitudinal studies with multi-modal measures of response inhibition can improve understanding of how response inhibition may intersect with substance use among adolescents. Most Stop-Signal studies suggest that slower response inhibition predicts substance use progressions, with one multi-site study showing greater fronto-parietal activity indicative of risk. Most Go-NoGo studies suggest that blunted activation of prefrontal cortical areas during response inhibition predicts substance use progressions, while commission errors are less effective in identifying adolescents at risk. Studies differ in subject populations, outcome measures, statistical methods, and BOLD response contrasts, which challenge the capacity to compare and generalize findings. We encourage research teams throughout the globe to undertake multi-modal, longitudinal studies to assess brain functioning with large sample sizes, and when possible, before significant substance use potentially obscures interpretation of findings. Systematic review and meta-analysis of this growing literature are also important goals for future research., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Cannabis use represents a major public health issue throughout the globe. Yet, we still lack the most fundamental knowledge on long-term effects of cannabis on neural, cognitive, and behavioral function. Part of this stems from how cannabis has been measured historically. To this end, most empirical examinations of cannabis have consolidated all types of cannabis collectively. However, this approach obscures differences in how cannabinoids operate. In this commentary, we address the contrasting properties of tetrahydrocannabinol (THC) and cannabidiol (CBD) and their opposing effects on cognitive function. In addition, we address the increase in cannabis potency throughout the past two decades and how that impacts generalizability of early data to evaluations of contemporary public health. We underscore the urgent need for future research to disaggregate examination of THC from CBD, along with the importance of measuring cannabis potency to more effectively unravel its influence on cognitive function and other health issues., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: In adolescence, psychological problems and regular use of alcohol, cigarettes, cannabis and other drugs (AOD) tend to cluster together, strongly indicating that certain groups of young people are at elevated risk of developing a problematic use of AOD., Objective: The aim of the present study was to develop an easy-to-implement screening instrument to identify subgroups of young people with different psychological problems at risk of problem use of AOD., Method: 3589 randomly selected young Danes between 15 and 25years of age, from a national survey (n=2702) and a municipality survey (n=887), answered a 12-item questionnaire (YouthMap12) with 6 items identifying externalizing problems (EP6) and 6 items identifying internalizing problems (IP6). Latent class analysis (LCA) was used to characterize groups at risk, and associations were estimated between EP6 and IP6 and regular use of AOD, and between latent class membership and regular use of AOD., Results: LCA identified 6 classes with varying degrees of externalizing and internalizing problems: 70% of youth were in the low problem score class, and the remaining 30% were at various levels of risk. Regular use of cigarettes, cannabis and alcohol was strongly associated with classes characterized by externalizing problems, while over-the-counter and prescription medicine was strongly associated with classes characterized by internalizing problems., Conclusions: Youth at risk of problem use of AOD can be identified using a simple and easily administered instrument., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Anhedonia, the lack of pleasure, has been shown to be a critical feature of a range of psychiatric disorders. Yet, it is currently measured primarily through subjective self-reports and as such has been difficult to submit to rigorous scientific analysis. New insights from affective neuroscience hold considerable promise in improving our understanding of anhedonia and for providing useful objective behavioral measures to complement traditional self-report measures, potentially leading to better diagnoses and novel treatments. Here, we review the state-of-the-art of hedonia research and specifically the established mechanisms of wanting, liking, and learning. Based on this framework we propose to conceptualize anhedonia as impairments in some or all of these processes, thereby departing from the longstanding view of anhedonia as solely reduced subjective experience of pleasure. We discuss how deficits in each of the reward components can lead to different expressions, or subtypes, of anhedonia affording novel ways of measurement. Specifically, we review evidence suggesting that patients suffering from depression and schizophrenia show impairments in wanting and learning, while some aspects of conscious liking seem surprisingly intact. Furthermore, the evidence suggests that anhedonia is heterogeneous across psychiatric disorders, depending on which parts of the pleasure networks are most affected. This in turn has implications for diagnosis and treatment of anhedonia.

The incentive sensitization theory is a promising model for understanding the mechanisms underlying drug addiction, and has received support in animal and human studies. So far the theory has not been applied to the case of behavioral addictions like Gambling Disorder, despite sharing clinical symptoms and underlying neurobiology. We examine the relevance of this theory for Gambling Disorder and point to predictions for future studies. The theory promises a significant contribution to the understanding of behavioral addiction and opens new avenues for treatment., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The introduction of magnetoencephalography has made it possible to study electromagnetic signaling in deeper, paralimbic cortical structures such as the medial prefrontal/anterior cingulate (ACC) and medial parietal/posterior cingulate (PCC) cortices. Self-awareness and self-control have been attributed to these regions. To test the hypothesis that they are dysfunctional in pathological gambling with poor self-control, we studied gamblers with and without previous stimulant abuse and age- and sex-matched controls. We found that pathological gamblers were more impulsive than controls in a stop-signal task and attributed this to changes in the activity of the paralimbic network: Pathological gamblers had reduced synchronization at rest in the high gamma range (55-100 Hz) compared with controls and failed to show an increase in gamma synchronization during rest compared with the task, as observed in controls. Subgroup analysis revealed that pathological gamblers without a history of stimulant abuse had lower PCC power during the stop-signal task compared with controls and gamblers with previous stimulant abuse. Furthermore, gamblers with a history of stimulant abuse had up to four times higher power at the ACC site during rest and the task compared with controls. In conclusion, pathological gamblers had higher impulsivity and functional paralimbic abnormalities, which could not be explained by a history of stimulant abuse. In addition, previous stimulant abuse had a marked effect on the amplitude of oscillatory brain activity in the ACC and PCC, suggesting long-term deleterious effects of repeated dopaminergic drug exposure. These consequences should be investigated in more detail in longitudinal studies.

Emotion and reward have been proposed to be closely linked to conscious experience, but empirical data are lacking. The anterior cingulate cortex (ACC) plays a central role in the hedonic dimension of conscious experience; thus potentially a key region in interactions between emotion and consciousness. Here we tested the impact of emotion on conscious experience, and directly investigated the role of the ACC. We used a masked paradigm that measures conscious reportability in terms of subjective confidence and objective accuracy in identifying the briefly presented stimulus in a forced-choice test. By manipulating the emotional valence (positive, neutral, negative) and the presentation time (16 ms, 32 ms, 80 ms) we measured the impact of these variables on conscious and subliminal (i.e. below threshold) processing. First, we tested normal participants using face and word stimuli. Results showed that participants were more confident and accurate when consciously seeing happy versus sad/neutral faces and words. When stimuli were presented subliminally, we found no effect of emotion. To investigate the neural basis of this impact of emotion, we recorded local field potentials (LFPs) directly in the ACC in a chronic pain patient. Behavioural findings were replicated: the patient was more confident and accurate when (consciously) seeing happy versus sad faces, while no effect was seen in subliminal trials. Mirroring behavioural findings, we found significant differences in the LFPs after around 500 ms (lasting 30 ms) in conscious trials between happy and sad faces, while no effect was found in subliminal trials. We thus demonstrate a striking impact of emotion on conscious experience, with positive emotional stimuli enhancing conscious reportability. In line with previous studies, the data indicate a key role of the ACC, but goes beyond earlier work by providing the first direct evidence of interaction between emotion and conscious experience in the human ACC.

The objective of this study was to investigate the relationship between gambling severity and depressive symptoms in pathological gamblers addicted to slot machines, with the hypothesis that comorbid depressive symptoms are associated with exacerbated gambling symptoms and behavior. Twenty controls and 20 pathological gamblers with different levels of depressive symptoms were studied during slot machine gambling. We found exacerbated gambling behavior in gamblers with high compared to low levels of depressive symptoms in terms of self-reported gambling urge (P < 0.01) and excitement from gambling (P < 0.05), number of games played (P < 0.01), and duration of gambling (P < 0.05). A correlation between depressive and gambling symptoms was found (r = 0.602, P < 0.01), thereby questioning which symptoms contribute to the exacerbated gambling behavior. Regression analyses showed that the symptoms influenced gambling behavior albeit in different ways. Although gambling symptoms predicted the rate of games played (P < 0.001), depressive symptoms predicted gambling urge (P < 0.01) and duration of gambling (P < 0.05). We discuss whether gambling symptoms only co-occur with other disorders; the need to look beyond the classification of pathological gambling as an impulse control disorder; and the potential role of anhedonia in depressed gamblers.