Search

Cannabis legislation and attitudes towards use are changing. Given that evidence from cultural neuroscience research suggests that culture influences the neurobiological mechanisms underlying behaviour, it is of great importance to understand how cannabis legislation and attitudes might affect the brain processes underlying cannabis use disorder. Brain activity of 100 dependent cannabis users and 84 controls was recorded during an N-back working memory (WM) task in participants from the Netherlands (NL; users = 60, controls = 52) and Texas, USA (TX; users = 40, controls = 32). Participants completed a cannabis culture questionnaire as a measure of perceived benefits (positive) and perceived harms (negative) of cannabis from their personal, friends-family's and country-state's perspectives. Amount of cannabis use (grams/week), DSM-5 CUD symptoms and cannabis use-related problems were assessed. Cannabis users self-reported more positive and less negative (personal and friends-family) cannabis attitudes than controls, with this effect being significantly larger in the TX cannabis users. No site difference in country-state attitudes was observed. TX cannabis users, compared with NL cannabis users, and those cannabis users perceiving more positive country-state attitudes showed a more positive association between grams/week and WM-related activity in the superior parietal lobe. NL cannabis users, compared with TX cannabis users, and those cannabis users with less positive personal attitudes showed a more positive association between grams/week and WM-load-related activity in the temporal pole. Both site and cultural attitudes moderated the association of quantity of cannabis use with WM- and WM-load-related activity. Importantly, differences in legislation did not align with perceived cannabis attitudes and appear to be differentially associated with cannabis use-related brain activity., (© 2023 The Authors. Addiction Biology published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Background: While cannabis use in women is increasing worldwide, research into gender differences in cannabis use disorder (CUD) symptomology is lacking. In response to limited effectiveness of addiction treatment, research focus has been shifting from clinical diagnoses towards interactions between symptoms, as patterns of symptoms and their interactions could be crucial in understanding etiological mechanisms in addiction. The aim of this study was to evaluate the CUD symptom network and assess whether there are gender differences therein., Methods: A total of 1257 Dutch individuals reporting weekly cannabis use, including 745 men and 512 women, completed online questionnaires assessing DSM-5 CUD symptoms and additional items on plans to quit or reduce use, cigarette use, and the presence of psychological diagnoses. Gender differences were assessed for all variables and an Ising model estimation method was used to estimate CUD symptom networks in men and women using network comparison tests to assess differences., Results: There were gender differences in the prevalence of 6 of the 11 symptoms, but symptom networks did not differ between men and women. Cigarette use appeared to only be connected to the network through withdrawal, indicating a potential role of cigarette smoking in enhancing cannabis withdrawal symptoms. Furthermore, there were gender differences in the network associations of mood and anxiety disorders with CUD symptoms., Conclusion: The association between smoking and withdrawal as well as gender differences in the role of comorbidities in the CUD network highlight the value of using network models to understand CUD and how symptom interactions might affect treatment., Competing Interests: Conflict of interest No conflict declared., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Aims: Cognitive and motivational processes are thought to underlie cannabis use disorder (CUD), but research assessing how cognitive processes [e.g. interference control (IC)] interact with implicit [e.g. attentional bias (AB)] and explicit motivation (i.e. craving) is lacking. We assessed the presence of AB in cannabis users with varying use severity and tested models of moderation, mediation and moderated mediation to assess how AB, craving and IC interact in their association with measures of cannabis use., Design: A cross-sectional study design was used., Setting and Participants: Eight studies performed by our laboratory in the Netherlands including never-sporadic, occasional (≤ 1/month) and regular cannabis users (≥ 2/week), and individuals in treatment for CUD were combined (n = 560; 71% male)., Measurements: Studies included a classic Stroop task (IC), a cannabis Stroop task (AB) and measures of session-induced and average session craving. Both heaviness of cannabis use (grams/week) and severity of use related problems were included., Findings: Only those in treatment for CUD showed an AB to cannabis (P = 0.019) and group differences were only observed when comparing CUD with never-sporadic users (P = 0.007). In occasional and regular users, IC was negatively associated with heaviness (β = 0.015, P < 0.001), but not severity of use. Average session craving (exploratory), but not session-induced craving (confirmatory), mediated this association between AB and heaviness (β = 0.050, P = 0.011) as well as severity of use (β = 0.083, P = 0.009); higher AB was associated with heavier use and more severe problems through increased craving., Conclusions: Attentional bias only appears to be present in cannabis users with the most severe problems and craving appears to mediate the association between attentional bias and both heaviness and severity of use in occasional and regular users. The association of interference control with heaviness but not severity of use may point to subacute intoxication effects of cannabis use on interference control., (© 2022 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Although cannabis use patterns differ between men and women, studies on sex differences on the effects of cannabis on the brain and cognitive control are largely lacking. Working memory (WM) is a component of cognitive control believed to be involved in the development and maintenance of addiction. In this study, we evaluated the association between cannabis use and WM (load) related brain activity in a large sample, enabling us to assess sex effects in this association. The brain activity of 104 frequent cannabis users (63% men) and 85 controls (53% men) was recorded during an N-back WM task. Behavioral results showed a significant interaction between WM load and group for both accuracy and reaction time, with cannabis users showing a relatively larger decrease in performance with increasing WM load. Cannabis users compared to controls showed a relatively smaller reduction in WM (load) related activity in the precuneus and posterior cingulate cortex at higher WM load. This WM (load) related activity was not associated with performance nor cannabis use and related problems. An exploratory analysis showed higher WM-related activity in the superior frontal gyrus in men compared to women. While cannabis users showed higher WM (load) related activity in central nodes of the default mode network, this was not directly attributable to group specific worsening of performance under higher cognitive load. Further research is necessary to assess whether observed group differences increase with higher cognitive load, how group differences relate to measures of cannabis use, and how sex affects these group differences., (© 2022 The Authors. Journal of Neuroscience Research published by Wiley Periodicals LLC.)

Rationale: Cannabis use among people with mood disorders increased in recent years. While comorbidity between cannabis use, cannabis use disorder (CUD), and mood disorders is high, the underlying mechanisms remain unclear., Objectives: We aimed to evaluate (1) the epidemiological evidence for an association between cannabis use, CUD, and mood disorders; (2) prospective longitudinal, genetic, and neurocognitive evidence of underlying mechanisms; and (3) prognosis and treatment options for individuals with CUD and mood disorders., Methods: Narrative review of existing literature is identified through PubMed searches, reviews, and meta-analyses. Evidence was reviewed separately for depression, bipolar disorder, and suicide., Results: Current evidence is limited and mixed but suggestive of a bidirectional relationship between cannabis use, CUD, and the onset of depression. The evidence more consistently points to cannabis use preceding onset of bipolar disorder. Shared neurocognitive mechanisms and underlying genetic and environmental risk factors appear to explain part of the association. However, cannabis use itself may also influence the development of mood disorders, while others may initiate cannabis use to self-medicate symptoms. Comorbid cannabis use and CUD are associated with worse prognosis for depression and bipolar disorder including increased suicidal behaviors. Evidence for targeted treatments is limited., Conclusions: The current evidence base is limited by the lack of well-controlled prospective longitudinal studies and clinical studies including comorbid individuals. Future studies in humans examining the causal pathways and potential mechanisms of the association between cannabis use, CUD, and mood disorder comorbidity are crucial for optimizing harm reduction and treatment strategies., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Rationale: Compromised cognitive control in cannabis use-tempting situations is thought to play a key role in the development of cannabis use disorders. However, little is known about how exposure to cannabis cues and contexts may influence cognitive control and the underlying neural mechanisms in cannabis users., Objectives: Working memory (WM) is an attention reliant executive function central to cognitive control. In this study, we investigated how distracting cannabis words affected WM load-dependent performance and related brain activity in near-daily cannabis users (N = 36) relative to controls (N = 33)., Methods: Brain activity was recorded during a novel N-back flanker WM task with neutral and cannabis flankers added as task-irrelevant distractors., Results: On a behavioural level, WM performance did not differ between groups, and the presence of cannabis flankers did not affect performance. However, in cannabis users compared to controls, the presence of cannabis flankers reduced WM load-related activity in multiple regions, including the insula, thalamus, superior parietal lobe and supramarginal gyrus., Conclusions: The group specificity of these effects suggest that cannabis users might differ from controls in the way they process cannabis-related cues and that cannabis cue exposure could interfere with other cognitive processes under cognitively demanding circumstances. Future studies should focus on the role of context in cognitive control-related processes like WM and attention to further elucidate potential cognitive impairments in heavy cannabis users and how these relate to loss of control over drug seeking itself., (© 2021. The Author(s).)

The aim of this review is to discuss the most recent evidence for the short-term and long-term effects of cannabis on cognition. The evidence that cannabis intoxication is associated with short-term impairment across several basal cognitive domains, including learning and (episodic) memory, attentional control, and motor inhibition is increasing. However, evidence regarding the effects of long-term heavy cannabis use on cognition remains equivocal. Cannabis research suffers from difficulties in measuring cannabis exposure history, poor control over potential subacute effects, and heterogeneity in cognitive measures and sample composition. Multidisciplinary collaborations and investment in studies that help overcome these difficulties should be prioritized., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The impact of cannabis on the adolescent compared to adult brain is of interest to researchers and society alike. From a theoretical perspective, adolescence represents a period of both risk and resilience to the harms of cannabis use and cannabis use disorders. The aim of this systematic review is to provide a critical examination of the moderating role of age on the relationship between cannabis use and cognition. To this end, we reviewed human and animal studies that formally tested whether age, adolescent or adult, changes the relationship between cannabis exposure and cognitive outcomes. While the results of this review do not offer a conclusive answer on the role of age, the novel review question, along with the inclusion of both human and animal work, has allowed for the formation of new hypotheses to be addressed in future work. First, general executive functioning seems to be more impaired in adolescent frequent cannabis users compared to adult frequent cannabis users. Second, age-effects may be most prominent among very heavy and dependent users. Third, craving and inhibitory control may not decrease as much post-intoxication in adolescents compared to adults. Lastly, adolescents' vulnerability to reduced learning following cannabis use may not persist after sustained abstinence. If these hypotheses prove correct, it could lead to important developments in policy and prevention efforts.

Background and aims: Lockdown measures aimed at limiting the number of infections and deaths from the coronavirus disease 2019 (COVID‐19) have introduced substantial psychosocial stressors in everyday life. We aimed to investigate the influence of the Dutch lockdown on cannabis use and cannabis use disorder (CUD) and investigate relations with change in mental wellbeing and experienced psychosocial stressors during the lockdown. Design Explorative longitudinal baseline‐, pre‐ and during lockdown survey study. Setting: The Netherlands, on‐line between January 2019 and May 2020. Participants: Community sample of 120 monthly to daily cannabis users and reference group of 63 non‐using controls. Measurements Change in cannabis use and CUD symptom severity from baseline to pre‐ to post‐lockdown. Change in cannabis use motives, mental health, quality of social relationships and job status from pre‐ to post‐lockdown. Findings In cannabis users, lockdown related to increased cannabis use [B = 1.96, 95% confidence interval (CI) = 0.26–3.66, P = 0.024], but not CUD symptom severity. Cannabis users experienced 30% job loss and increased loneliness [P < 0.001, Bayes factor (BF)10 > 100], while contact with partners (P = 0.005, BF10= 8.21) and families improved (P < 0.001, BF10 = 19.73), with no differences between cannabis users and control. Generally, mental health problems (all Ps > 0.277, all BF10 < 0.139) did not change, but individual differences were significant and severity of cannabis use pre‐lockdown, COVID‐19‐related worries, change in anxiety, expansion motives, social motives and family contact all uniquely related to variance in change in cannabis use or CUD. Conclusions: While cannabis use among daily cannabis users in the Netherlands increased at the group level during the period of COVID‐19 lockdown, the effect of the first months of lockdown on cannabis use disorder severity and mental wellbeing varied significantly among individual daily cannabis users. [ABSTRACT FROM AUTHOR]