Time to acknowledge the mixed effects of cannabis on health: a summary and critical review of the NASEM 2017 report on the health effects of cannabis and cannabinoids

This is a summary and critical review of the National Academies of Sciences, Engineering and Medicine (NASEM) report of the health effects of cannabis. The report stated that effects of cannabis are understudied, and research findings are mixed. It concluded that the under‐developed evidence base poses a public health risk and rightly addressed complexities of cannabis research that need to be resolved collaboratively. We support NASEM's urgent call for research, but add that the mixed evidence base cannot be attributed solely to research limitations. Rather, we propose a need to acknowledge the heterogeneity in the effects of cannabis to advance the field

Determining Risks for Cannabis Use Disorder in the Face of Changing Legal Policies

Purpose of Review: This review aims to summarize and critically evaluate the current literature on the associations between individual and socio-cultural factors that increase risk for cannabis use disorder (CUD), and policy change. Recent findings: Epidemiological studies show that areas with permissive legal cannabis climates are associated with greater individual risk factors for CUD. This includes (1) higher rates of edible consumption and vaping, (2) higher delta-9-tetrahydrocannabinol (THC) potency and lower cannabidiol (CBD) levels, and (3) younger age of initiation of use. Summary: A change in the socio-cultural level, such as shifts in the legalization of cannabis, could interact with individual-level factors in their associations with CUD. There is currently a lack of empirical studies that evaluate this interaction. We propose that future research consider a bioecological framework for CUD to allow for a comprehensive understanding of the effects of legal climate that could inform policy and clinical practice

Context dependent differences in working memory related brain activity in heavy cannabis users

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