Impact of cannabis decriminalization on selected psychotic disorders: a retrospective analysis at the Center for Mental Health and Prevention of Addiction (2013–2023) in Tbilisi
L. Jishkariani, D. Zurabashvili, K. Gigolashvili, N. Jibuti, K. Jmukhadze, G. Lezhava, Y. Jung, M. Kim
European Psychiatry June 1, 2026 DOI: 10.1192/j.eurpsy.2026.10495 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Retrospective observational review Peer reviewed |
|---|---|
| Sample size | 12,680 |
| Population | Adult psychiatric inpatients at the Tbilisi Mental Health and Prevention of Addiction Center, Georgia, 2013-2023 |
| Duration | 2013-2023 (pre-decriminalization 2013-2018; post-decriminalization 2019-2023) |
| Topics | Addiction Cannabis |
| Key findings | After Georgia's 2018 cannabis decriminalization, unique cases of acute and transient psychotic disorder tripled (195 to 594) and substance-related psychotic cases rose fourfold (243 to 907), with cannabis implicated in over 70% of post-2018 substance cases and the proportion of psychosis cases involving substance use rising from 9.6% to 81.4%. The authors suggest a potential link between cannabis policy change and psychosis incidence, while noting that declines in F20.0 and F06.2 may reflect chronicity and under-detection in inpatient settings. |
Abstract
Introduction: Cannabis decriminalization raises concerns about its psychiatric impact, particularly on psychosis risk. As cannabis became decriminalized in Georgia in 2018, questions emerged regarding changes in substance-related and acute psychotic disorders. Examining these trends is essential to guide prevention, treatment, and policy in a shifting drug landscape.
Objectives: This study aims to: assess changes in rates of substance-associated psychoses following Georgia’s 2018 cannabis decriminalization; examine diagnostic trends in acute/transient psychoses and cannabinoid-related disorders; explore clinical and policy implications of observed patterns.
Methods: A retrospective review was conducted of all adult psychiatric inpatient admissions (n = 12,680) at the Tbilisi Mental Health and Prevention of Addiction Center between 2013 and 2023. Unique first-time cases diagnosed with F23.0 (n = 789), F20.0 (n = 2,359), and F06.2 (n = 490) were extracted. Cases were stratified into pre-decriminalization (2013–2018) and post-decriminalization (2019–2023) periods. Substance use status, sex distribution, and diagnostic trends were analyzed descriptively.
Results: Following decriminalization, the number of unique ATPD cases tripled (from 195 to 594). Substance-related psychotic cases increased fourfold (from 243 to 907), with cannabis implicated in over 70% of post-2018 substance cases. The proportion of psychosis cases involving substance use rose from 9.6% pre-2018 to 81.4% post-2018. Cannabis-only use increased 4.2-fold; polysubstance use increased 3.2-fold. Substance-using cases were overwhelmingly male (96%). F20.0 and F06.2 incidence showed a relative decline, potentially reflecting chronicity and under-detection in inpatient settings. Image 1: Image 1: Long description.A comparative table showing unique cases and drug user ratios across four medical categories for the periods 2013-2017 and 2018-2023. See long description.
Conclusions: A significant post-decriminalization rise in ATPD, predominantly among substance-using males, suggests a potential link between cannabis policy changes and psychosis incidence. The findings highlight the need for evidence-based prevention strategies, gender-responsive interventions, integrated dual-diagnosis care, and robust national monitoring systems. Disclosure of Interest None Declared
Comparable studies
Other observational and cohort studies on cannabis for addiction, most cited first.