Cannabis Use Explains Little of the Higher Psychosis Risk in European Ethnic Minorities
Across five European countries, cannabis use accounted for very little of the elevated psychosis risk among non-Western ethnic minorities, with two notable exceptions among specific Caribbean and Surinamese groups.
Quick Facts
What This Study Found
The odds ratio for psychotic disorder among non-Western minorities was 1.80, and adjusting for cannabis use frequency barely changed it (1.81). However, for Black Caribbean individuals in London, adjusting for high-potency cannabis use reduced the OR from 2.45 to 1.61, and for Surinamese/Dutch Antillean individuals in Amsterdam, adjusting for daily use reduced the OR from 2.57 to 1.67.
Key Numbers
Overall non-Western minority OR: 1.80 (95% CI: 1.39-2.33), minimally changed after cannabis adjustment: 1.81. Black Caribbean in London: OR dropped from 2.45 to 1.61 after high-potency cannabis adjustment. Surinamese/Dutch Antillean in Amsterdam: OR dropped from 2.57 to 1.67 after daily use adjustment. 825 patients and 1,026 controls across 5 countries.
How They Did This
Case-control study using EU-GEI data from Spain, Italy, France, UK, and Netherlands. 825 first-episode psychosis patients and 1,026 controls were compared. Odds ratios for psychosis were calculated for migrant groups with and without adjustment for cannabis use measures.
Why This Research Matters
The elevated psychosis risk among ethnic minorities in Europe is well-documented but poorly understood. This study tests whether cannabis use, itself a risk factor for psychosis, explains the gap. For most groups, it does not, pointing to other factors like social adversity, discrimination, or urbanicity.
The Bigger Picture
This finding challenges a simple narrative that cannabis drives the ethnic disparity in psychosis rates. While cannabis use may contribute in specific subgroups, the broader picture suggests social and structural factors play a larger role for most minority populations in Europe.
What This Study Doesn't Tell Us
Case-control design has inherent limitations in establishing causation. Cannabis use was self-reported and may be underreported. The two subgroups where cannabis appeared to matter (Black Caribbean, Surinamese) had relatively small sample sizes, making those estimates less stable.
Questions This Raises
- ?Why does cannabis appear to play a role for Black Caribbean and Surinamese groups but not others?
- ?Is it higher rates of high-potency use, different genetic vulnerability, or interaction with other social risk factors?
- ?What factors beyond cannabis explain the elevated risk?
Trust & Context
- Key Stat:
- Adjusting for cannabis barely changed the 1.80 odds ratio for psychosis in minorities
- Evidence Grade:
- Large multi-country case-control study with appropriate adjustment for confounders, from a well-established research consortium.
- Study Age:
- 2024 study
- Original Title:
- The contribution of cannabis use to the increased psychosis risk among minority ethnic groups in Europe.
- Published In:
- Psychological medicine, 54(11), 2937-2946 (2024)
- Authors:
- Selten, J P, Di Forti, M(4), Quattrone, D(4), Jones, P B, Jongsma, H E, Gayer-Anderson, C, Szöke, A, Llorca, P M, Arango, C, Bernardo, M, Sanjuan, J, Santos, J L, Arrojo, M, Tarricone, I, Berardi, D, Lasalvia, A, Tosato, S, la Cascia, C, Velthorst, E, van der Ven, E M A, de Haan, L, Rutten, B P, van Os, J, Kirkbride, J B, Morgan, C M, Murray, R M, Termorshuizen, F
- Database ID:
- RTHC-05696
Evidence Hierarchy
Compares people with a condition to similar people without it.
What do these levels mean? →Frequently Asked Questions
Does cannabis explain why ethnic minorities have higher psychosis rates?
Mostly not. Across five European countries, adjusting for cannabis use barely changed the elevated psychosis risk for non-Western minorities. Cannabis appeared to play a partial role only for Black Caribbean people in London and Surinamese/Dutch Antillean people in Amsterdam.
Did high-potency cannabis matter more?
For the Black Caribbean group in London, adjusting specifically for high-potency cannabis use reduced the odds ratio from 2.45 to 1.61, suggesting potency may be a factor in that specific population.
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Cite This Study
https://rethinkthc.com/research/RTHC-05696APA
Selten, J P; Di Forti, M; Quattrone, D; Jones, P B; Jongsma, H E; Gayer-Anderson, C; Szöke, A; Llorca, P M; Arango, C; Bernardo, M; Sanjuan, J; Santos, J L; Arrojo, M; Tarricone, I; Berardi, D; Lasalvia, A; Tosato, S; la Cascia, C; Velthorst, E; van der Ven, E M A; de Haan, L; Rutten, B P; van Os, J; Kirkbride, J B; Morgan, C M; Murray, R M; Termorshuizen, F. (2024). The contribution of cannabis use to the increased psychosis risk among minority ethnic groups in Europe.. Psychological medicine, 54(11), 2937-2946. https://doi.org/10.1017/S0033291724001004
MLA
Selten, J P, et al. "The contribution of cannabis use to the increased psychosis risk among minority ethnic groups in Europe.." Psychological medicine, 2024. https://doi.org/10.1017/S0033291724001004
RethinkTHC
RethinkTHC Research Database. "The contribution of cannabis use to the increased psychosis ..." RTHC-05696. Retrieved from https://rethinkthc.com/research/selten-2024-the-contribution-of-cannabis
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.