Background and Aims: Cannabis withdrawal is a well‐characterized phenomenon that occurs in approximately half of regular and dependent cannabis users after abrupt cessation or significant reductions in cannabis products that contain Δ⁹‐tetrahydrocannabinol (THC). This review describes the diagnosis, prevalence, course and management of cannabis withdrawal and highlights opportunities for future clinical research.Methods: Narrative review of literature.Results: Symptom onset typically occurs 24–48 hours after cessation and most symptoms generally peak at days 2–6, with some symptoms lasting up to 3 weeks or more in heavy cannabis users. The most common features of cannabis withdrawal are anxiety, irritability, anger or aggression, disturbed sleep/dreaming, depressed mood and loss of appetite. Less common physical symptoms include chills, headaches, physical tension, sweating and stomach pain. Despite limited empirical evidence, supportive counselling and psychoeducation are the first‐line approaches in the management of cannabis withdrawal. There are no medications currently approved specifically for medically assisted withdrawal (MAW). Medications have been used to manage short‐term symptoms (e.g. anxiety, sleep, nausea). A number of promising pharmacological agents have been examined in controlled trials, but these have been underpowered and positive findings not reliably replicated. Some (e.g. cannabis agonists) are used ‘off‐label’ in clinical practice. Inpatient admission for MAW may be clinically indicated for patients who have significant comorbid mental health disorders and polysubstance use to avoid severe complications.Conclusions: The clinical significance of cannabis withdrawal is that its symptoms may precipitate relapse to cannabis use. Complicated withdrawal may occur in people with concurrent mental health and polysubstance use.

Aims: We provide a narrative summary of research on changes in cannabis arrests, cannabis products and prices, cannabis use and cannabis‐related harm since legalization.Methods: We systematically searched for research on the impacts of cannabis legalization in Canada in PubMed, Embase, Statistics Canada and government websites and Google Scholar, published between 2006 and 2021.Results: Cannabis legalization in Canada has been followed by substantial reductions in cannabis‐related arrests and cannabis prices. It has also increased adults’ access to a diverse range of cannabis products, including edibles and extracts. The prevalence of cannabis use among young adults has increased, but there have been no marked increases or decreases in use among high school students or changes in the prevalence of daily or near‐daily use. Legalization has been associated with increased adult hospital attendances for psychiatric distress and vomiting, unintentional ingestion of edible cannabis products by children and hospitalizations for cannabis use disorders in adults. There is conflicting evidence on whether cannabis‐impaired driving has increased since legalization. There is suggestive evidence that presentations to emergency departments with psychoses and cannabis use disorders may have increased since legalization.Conclusions: Legalization of cannabis in Canada appears to have reduced cannabis arrests and increased access to a variety of more potent cannabis products at lower prices. Since 2019, recent cannabis use in Canada has modestly increased among adults but not among adolescents. There is evidence of increased acute adverse effects of cannabis among adults and children.

Aims: There is a growing body of literature exploring the types of substance‐related content and their portrayals on various social media platforms. We aimed to summarize how content related to substances is portrayed on various social media platforms.Methods: This systematic review was pre‐registered on PROSPERO (ref: CRD42021291853). A comprehensive search was conducted in the databases of PubMed, Scopus, PsycINFO and Web of Science in April 2021. Original qualitative studies published post‐2004 that included thematic and sentiment analyses of social media content on tobacco, alcohol, psychostimulant, e‐cigarette, cannabis, opiate, stimulant/amphetamine, inhalant and novel psychoactive substance were included. Social media platforms were defined as online web‐ or application‐based platforms that allowed users to generate content and interact via ‘liking’, comment or messaging features. Only studies that included summative and/or thematic content analyses of substance‐related social media content were included.Results: A total of 73 studies, which covered 15 905 182 substance‐related posts on Twitter, YouTube, Instagram, Pinterest, TikTok and Weibo, were identified. A total of 76.3% of all substance‐related content was positive in its depiction of substance use, with 20.2% of content depicting use negatively. Sentiment regarding opiate use however was commonly negative (55.5%). Most studies identified themes relating to Health, Safety and Harms (65.0%) of substance use. Themes relating to Promotions/Advertisements (63.3%), Informative content (55.0%) and Use behaviours (43.3%) were also frequently identified.Conclusions: Substance‐related content that promotes engagement with substance use or actively depicts use appears to be widely available on social media. The large public presence of this content may have concerning influences on attitudes, behaviours and risk perceptions relating to substance use, particularly among the most vulnerable and heaviest users of social media—adolescents and young adults.

Background and Aims: Heated tobacco products (HTPs) are electronic devices that heat process tobacco to release an aerosol containing nicotine and other chemicals. Limited data exist on world‐wide HTP use prevalence. This meta‐analytic review estimated the prevalence of HTP use by country, World Health Organization (WHO) region, year, sex/gender and age.Methods: Five databases (Web of Science, Scopus, Embase, PubMed and PsycINFO) were searched between January 2015 and May 2022. Included studies reported the prevalence of HTP use in nationally representative samples post‐modern HTP device market entry (2015). A random‐effects meta‐analysis was used to estimate overall prevalence for life‐time, current and daily HTP use.Results: Forty‐five studies (n = 1 096 076) from 42 countries/areas from the European Region (EUR), Western Pacific Region (WPR), Region of the Americas (AMR) and African Region (AFR) met inclusion criteria. Estimated pooled prevalence for life‐time, current and daily HTP use was 4.87% [95% confidence interval (CI) = 4.16, 5.63], 1.53% (95% CI = 1.22, 1.87) and 0.79% (95% CI = 0.48, 1.18), respectively, across all years (2015–22). Life‐time HTP use prevalence significantly increased by 3.39% for WPR [0.52% (95% CI = 0.25, 0.88) in 2015 to 3.91% (95% CI = 2.30, 5.92) in 2019] and 5.58% for EUR [1.13% (95% CI = 0.59, 1.97) in 2016 to 6.98% (95% CI = 5.69, 8.39) in 2020]. Current HTP use increased by 10.45% for WPR [0.12% (95% CI = 0, 0.37) in 2015 to 10.57% (95% CI = 5.59, 16.88) in 2020] and 1.15% for EUR [0% (95% CI = 0, 0.35) in 2016 to 1.15% (95% CI = 0.87, 1.47) in 2020]. Meta‐regression revealed higher current HTP use in WPR [3.80% (95% CI = 2.88, 4.98)] compared with EUR [1.40% (95% CI = 1.09, 1.74)] and AMR [0.81% (95% CI = 0.46, 1.26)] and for males [3.45% (95% CI = 2.56, 4.47)] compared with females [1.82% (95% CI = 1.39, 2.29)]. Adolescents had higher life‐time HTP use prevalence [5.25% (95% CI = 4.36, 6.21) than adults [2.45% (95% CI = 0.79, 4.97)]. Most studies scored a low risk of sampling bias due to their nationally representative sampling.Conclusion: The prevalence of HTPs use increased in the EUR and WPR between 2015 and 2020, with nearly 5% of the included populations having ever tried HTP and 1.5% identifying as current users during the study period.

Significance: Traditional laboratory-based fear-conditioning approaches are often limited in their generalizability to real-world encounters where threats are dynamic and embedded in contextually rich environments. Moreover, while spatial distance to a threat organizes defensive responses, our understanding of the neurobehavioral mechanisms relating proximity and fear learning is lacking. To address these limitations, we developed a three-dimensional (3D) virtual reality simulation that provides a more ecologically valid examination of how threat proximity influences the learning and memory of fear associations. Our findings highlight that threats invading peripersonal space persist longer in memory and uniquely recruit a reactive neural fear system, which has important clinical implications for understanding how near-body traumatic experiences exacerbate the development of traumatic stress disorders.