Cannabis use worsened disorganized thinking in people at risk for psychosis but did not trigger transition to psychotic disorders | Research

The takeaway

Among people showing early signs of psychosis risk, cannabis use was linked to worse disorganization symptoms but did not increase the rate of transition to full psychotic disorders over 2.5 years.

Clinicians working with early psychosis populations; researchers studying cannabis as a risk factor for psychotic disorders.

109 at-risk individuals followed 2.5 years; no increase in transition to psychosis

What the researchers found

In a community sample of 109 at-risk individuals and 197 controls from Sao Paulo, Brazil, cannabis use patterns did not differ between the two groups and did not predict transition to psychiatric disorders. However, among the at-risk group, cannabis use was significantly associated with more severe disorganization symptoms.

Why it matters

Most studies on cannabis and psychosis risk recruit from clinical settings. This study used a community sample of people not seeking help, providing a different perspective on how cannabis affects early psychosis risk in the general population.

The numbers in context

109 at-risk individuals and 197 controls were followed for a mean of 2.5 years. No significant differences in lifetime, current, or maximum cannabis use between groups. Cannabis use significantly correlated with disorganization symptoms in the at-risk group.

How the study worked

Prospective cohort study drawing from the general population (non-help-seeking) with 2.5-year follow-up. Cannabis use was assessed with the South Westminster modified questionnaire. Transition to psychiatric disorders was tracked through reassessment.

What this study cannot tell us

Relatively small sample size for transition analysis. Self-reported cannabis use. Community-based sample may have milder risk profiles than clinical populations. 2.5-year follow-up may be too short to capture all transitions.

How to read the evidence

Prospective cohort with community sampling, though modest sample size limits transition analysis.

When this study was published

2024 study

The bigger picture

The finding that cannabis worsens specific symptom dimensions without accelerating full transition adds nuance to the cannabis-psychosis debate, suggesting the relationship may be more about symptom severity than triggering new disorders.

Questions still open

Why does cannabis specifically worsen disorganization rather than other symptom domains? Would longer follow-up reveal eventual transitions?

Common questions

What are disorganization symptoms?

Disorganization refers to disordered thinking, speech, and behavior, such as jumping between unrelated topics, difficulty organizing thoughts, or behaving in ways that seem random or purposeless.

Does this mean cannabis is safe for people at risk of psychosis?

Not necessarily. Cannabis was associated with worse symptoms even if it did not trigger full transition in this study. The sample was small and follow-up relatively short.

Read the original research

Cannabis use influences disorganized symptoms severity but not transition in a cohort of non-help-seeking individuals at-risk for psychosis from São Paulo, Brazil.

Psychiatry research, 331, 115665

View on PubMed ↗Publisher’s paper ↗

Citation

de Medeiros, Matheus Wanderley; Andrade, Julio Cesar; Haddad, Natalia Mansur; Mendonça, Melina; de Jesus, Leonardo Peroni; Fekih-Romdhane, Feten; van de Bilt, Martinus Theodorus; Gattaz, Wagner Farid; Loch, Alexandre Andrade. (2024). Cannabis use influences disorganized symptoms severity but not transition in a cohort of non-help-seeking individuals at-risk for psychosis from São Paulo, Brazil.. Psychiatry research, 331, 115665. https://doi.org/10.1016/j.psychres.2023.115665