Cannabis Use Significantly Increases Suicide Risk in First-Episode Psychosis Patients | Research

The takeaway

A systematic review of 50 studies involving 12,764 first-episode psychosis patients found regular cannabis use nearly tripled suicide risk, with daily use and high-THC products carrying the greatest danger.

Psychiatrists managing psychosis, crisis intervention teams, families of individuals with psychotic disorders.

Daily cannabis use: 2.73x suicide risk in FEP

What the researchers found

Across 50 studies (12,764 FEP patients), cannabis use consistently elevated suicide risk (OR 1.43-1.84), with daily use showing OR 2.73 (95% CI 1.89-3.94) and high-THC cannabis OR 3.12 (95% CI 2.11-4.62). Mechanisms included neurobiological alterations, depressive symptom exacerbation, impaired cognition, increased duration of untreated psychosis, and reduced treatment adherence. Critical high-risk periods: first month after treatment initiation and post-discharge.

Why it matters

Suicide is the leading cause of premature death in psychosis patients, and this review shows cannabis dramatically amplifies that risk. The dose-response relationship, with daily and high-potency use carrying the most risk, provides specific guidance for clinical risk assessment and intervention timing.

The numbers in context

50 studies, 12,764 FEP patients. Overall OR 1.43-1.84. Daily use OR 2.73. High-THC OR 3.12. Early onset (<age 15-16) is key vulnerability. High-risk periods: 1st month of treatment, post-discharge. Female sex, childhood trauma as vulnerability factors.

How the study worked

Systematic review following PRISMA guidelines analyzing 50 studies involving 12,764 first-episode psychosis patients. Examined cannabis-suicide relationship, underlying mechanisms, moderating factors, and intervention strategies.

What this study cannot tell us

Mostly observational studies. Cannot fully establish causation. Suicide is rare even in high-risk populations, limiting statistical precision. THC potency was not measured directly in most studies. Cannot determine whether cannabis causes suicidality or whether suicidal patients are more likely to use cannabis.

How to read the evidence

Strong: large systematic review (50 studies, 12,764 patients) with consistent dose-response relationships and identified mechanisms.

When this study was published

2025 study

The bigger picture

As cannabis potency increases globally, the suicide risk for psychosis patients who use cannabis may be rising. The identification of specific high-risk periods (early treatment, post-discharge) enables targeted intervention protocols that could save lives.

Questions still open

Would cannabis cessation programs specifically targeting FEP patients reduce suicide rates? Should cannabis use screening be mandatory in psychiatric risk assessment? Could CBD counteract THC-related suicide risk in psychosis patients?

Common questions

Does cannabis increase suicide risk in psychosis patients?

Yes, significantly. This review found cannabis use was associated with 1.43-1.84 times higher suicide risk in first-episode psychosis patients, rising to 2.73 times with daily use and 3.12 times with high-THC cannabis.

When are cannabis-using psychosis patients at highest suicide risk?

The first month after starting treatment and the period following hospital discharge were identified as critical high-risk windows, suggesting these periods need intensive monitoring and intervention.

Read the original research

Cannabis and suicide risk in first-episode psychosis: Mechanisms, interactions, and intervention strategies.

Asian journal of psychiatry, 110, 104624

View on PubMed ↗Publisher’s paper ↗

Citation

Ricci, Valerio; Sarni, Alessandro; Barresi, Marialuiga; Remondino, Lorenzo; Martinotti, Giovanni; Maina, Giuseppe. (2025). Cannabis and suicide risk in first-episode psychosis: Mechanisms, interactions, and intervention strategies.. Asian journal of psychiatry, 110, 104624. https://doi.org/10.1016/j.ajp.2025.104624