Cannabis and suicide risk in first-episode psychosis: Mechanisms, interactions, and intervention strategies.
Valerio Ricci, Alessandro Sarni, Marialuiga Barresi, Lorenzo Remondino, Giovanni Martinotti, Giuseppe Maina
Asian Journal of Psychiatry July 10, 2025 DOI: 10.1016/j.ajp.2025.104624 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Systematic review Peer reviewed |
|---|---|
| Sample size | 12,764 |
| Population | First-episode psychosis (FEP) patients |
| Topics | Cannabis |
| Key findings | The authors conclude that cannabis use, especially high-potency and daily use, is associated with increased suicide risk in first-episode psychosis patients, with reported odds ratios of 1.43-1.84 overall, 2.73 for daily use, and 3.12 for high-THC cannabis. They propose multiple mediating mechanisms and identify early-onset use, female gender, childhood trauma, and comorbid disorders as vulnerability factors. |
Abstract
Cannabis use represents a significant risk factor for both psychotic disorders and suicidal behaviors, with growing evidence suggesting complex interactions between these variables. This systematic review examines the relationship between cannabis use and suicide risk in first-episode psychosis (FEP) patients, and explores underlying mechanisms, moderating factors, and intervention strategies. Following PRISMA guidelines, we analyzed 50 studies involving 12,764 FEP patients. Results demonstrate that cannabis use, especially high-potency cannabis used regularly, is associated with significantly increased suicide risk with studies consistently reporting elevated odds ratios (ranging from 1.43 to 1.84), and dose-dependent effects-daily use showing higher risk (studies reporting OR: 2.73, 95 % CI: 1.89-3.94) and high-THC cannabis carrying greatest risk (OR: 3.12, 95 % CI: 2.11-4.62). Multiple mechanisms mediate this relationship: neurobiological alterations in the endocannabinoid system, exacerbation of depressive symptoms, impaired cognitive functions, increased duration of untreated psychosis, and reduced treatment adherence. Key vulnerability factors include early-onset cannabis use (before age 15-16), female gender, history of childhood trauma, and comorbid psychiatric disorders. Critical high-risk periods were identified, particularly the first month after treatment initiation and following hospital discharge. Effective intervention strategies include integrated early intervention programs combining pharmacological treatment with psychosocial approaches, specifically cognitive-behavioral therapy, motivational interviewing, and family interventions. Emerging evidence suggests potential therapeutic benefits of CBD and specific risk management protocols. This review highlights the clinical importance of assessing cannabis use patterns in FEP patients and implementing targeted interventions during critical periods, particularly given the increasing availability of high-potency cannabis products globally.
Comparable studies
Other systematic reviews and meta-analyses on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Effects of cannabis use on outcomes of psychotic disorders: systematic review People with psychotic disorders, as examined in 13 longitudinal studies | 2008 | Systematic review | |
| The Impact of Cannabis Use on Cognitive Functioning in Patients With Schizophrenia: A Meta-analysis of Existing Findings and New Data in a First-Episode Sample Patients with established schizophrenia (meta-analysis: 572) and patients with... | 2010 | Meta-analysis and cross-sectional observational study | n = 700 |
| Medicinal cannabis for psychiatric disorders: a clinically-focused systematic review | 2020 | Systematic review | |
| Neuroimaging in cannabis use: a systematic review of the literature Cannabis users and controls in neuroimaging studies | 2009 | Systematic review | |
| Human Laboratory Studies on Cannabinoids and Psychosis. Healthy human subjects and individuals with schizophrenia | 2016 | Systematic review |
Citations in the library
Cited by 2
- How adolescent cannabis use reshapes the developing brain — a systematic review Frontiers in Psychiatry April 27, 2026
- Multi-dimensional recovery trajectories in cannabis-induced psychosis: A systematic review examining symptomatic, functional, cognitive, and subjective outcomes. Asian Journal of Psychiatry April 1, 2026
Cites 13
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