25% of Medical Cannabis Patients Had Suicidal Thoughts at Treatment Entry, With Rates Declining Over 12 Months

What the researchers found

At treatment entry, 25% of patients reported suicidal ideation. Those with SI had significantly higher depression scores (17.4 vs 11.3), lower well-being, and lower quality of life. After 3 months of cannabis-based medicinal product treatment, suicidal ideation significantly decreased. Over 12 months, depression scores dropped substantially in those with initial SI (17.7 to 10.3) and in other patients (11.1 to 7.0).

Why it matters

Medical cannabis patients have high rates of mental health comorbidities, and suicidal ideation in this population is underrecognized. The finding that SI decreased with treatment is important, though the observational design means this could reflect regression to the mean or other factors.

The numbers in context

3,781 patients at entry, 25% with SI. SI group depression score: 17.4 vs 11.3 (p<0.001). SI decreased significantly at 3 months (z=6.5, p<0.001). 12-month depression change: SI group 17.7 to 10.3; others 11.1 to 7.0. Follow-up: 2,112 at 3 months, 777 at 12 months.

How the study worked

Prospective observational study of 3,781 patients at treatment entry, with follow-up data for 2,112 at 3 months and 777 at 12 months. Suicidal ideation and depression assessed using PHQ-9 items. Additional data on demographics and well-being.

What this study cannot tell us

Observational with no control group. Large dropout from 3,781 to 777 over 12 months introduces selection bias. Self-reported SI may be underreported. Cannot determine whether cannabis treatment caused improvement. PHQ-9 is a screening tool, not a diagnostic assessment.

How to read the evidence

Moderate: large prospective cohort with validated measures, but no control group, high dropout, and observational design limit causal inference.

When this study was published

2025 study.

The bigger picture

This study highlights that medical cannabis patients are a psychologically vulnerable population. Whether cannabis treatment itself contributes to the improvement in suicidal ideation or whether other factors are responsible cannot be determined from this design.

Questions still open

• Does medical cannabis directly reduce suicidal ideation or is the improvement due to treating underlying pain/symptoms? Should medical cannabis providers routinely screen for suicidal ideation? Could some cannabis products worsen SI in vulnerable patients?

Common questions

Read the original research

Suicidal Ideation in Medicinal Cannabis Patients: A 12-Month Prospective Study.

Archives of suicide research : official journal of the International Academy for Suicide Research, 29(2), 407-421

Citation

Lynskey, M T; Thurgur, H; Athanasiou-Fragkouli, A; Schlag, A K; Nutt, D J. (2025). Suicidal Ideation in Medicinal Cannabis Patients: A 12-Month Prospective Study.. Archives of suicide research : official journal of the International Academy for Suicide Research, 29(2), 407-421. https://doi.org/10.1080/13811118.2024.2356615

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