Cannabis use partially explained the link between childhood adversity and psychosis in a large European study | Research

The takeaway

In the EU-GEI study of 881 first-episode psychosis patients and 1,231 controls, cannabis use patterns partially mediated the relationship between childhood adversity and psychotic disorders.

Psychiatrists, trauma researchers, youth mental health professionals, and psychosis prevention specialists.

881 FEP patients, 1,231 controls; cannabis use partially mediated adversity-psychosis link

What the researchers found

Cannabis use acted as a partial mediator between childhood adversity and first-episode psychosis. Different patterns of cannabis use (frequency, potency, duration) contributed to this mediating pathway, suggesting adversity may increase psychosis risk partly through promoting problematic cannabis use.

Why it matters

Understanding whether cannabis use is a mechanism linking childhood adversity to psychosis could inform prevention. If adversity increases psychosis risk partly by promoting cannabis use, targeting substance use in trauma-exposed youth could reduce psychosis incidence.

The numbers in context

881 first-episode psychosis patients and 1,231 controls from the EU-GEI study across Europe. Cannabis use patterns partially mediated the childhood adversity-psychosis association.

How the study worked

Case-control study using EU-GEI data. 881 first-episode psychosis patients and 1,231 controls. Detailed cannabis use histories collected. Mediation analysis tested whether cannabis use patterns explained part of the adversity-psychosis association.

What this study cannot tell us

Case-control design limits causal inference. Retrospective assessment of both childhood adversity and cannabis use history. Mediation analysis assumes temporal ordering that cannot be confirmed. Other mediating pathways (e.g., stress, other substances) not fully examined.

How to read the evidence

Large multi-site case-control study with detailed exposure data. Retrospective design and unmeasured confounders limit causal claims.

When this study was published

Published 2023.

The bigger picture

Childhood adversity and cannabis use are both established risk factors for psychosis, but they have been studied largely in isolation. This mediation analysis reveals a potential pathway: adversity leads to cannabis use, which in turn increases psychosis risk.

Questions still open

Would prospective studies starting in childhood confirm this mediation pathway? Could reducing cannabis use in adversity-exposed youth demonstrably lower psychosis incidence?

Common questions

Does childhood trauma cause psychosis through cannabis use?

This study found cannabis use partially explains the link between childhood adversity and psychosis, but it is not the only pathway. People who experienced childhood adversity were more likely to develop heavier cannabis use patterns, which in turn increased their psychosis risk. Other mechanisms also contribute.

Should trauma-exposed youth avoid cannabis?

This data suggests trauma-exposed individuals may be at particularly elevated psychosis risk from cannabis use, since cannabis use mediates part of the adversity-psychosis relationship. However, the study cannot prove that avoiding cannabis would eliminate the added risk, as other pathways from adversity to psychosis also exist.

Read the original research

Cannabis use as a potential mediator between childhood adversity and first-episode psychosis: results from the EU-GEI case-control study.

Psychological medicine, 53(15), 7375-7384

View on PubMed ↗Publisher’s paper ↗

Citation

Trotta, Giulia; Rodriguez, Victoria; Quattrone, Diego; Spinazzola, Edoardo; Tripoli, Giada; Gayer-Anderson, Charlotte; Freeman, Tom P; Jongsma, Hannah E; Sideli, Lucia; Aas, Monica; Stilo, Simona A; La Cascia, Caterina; Ferraro, Laura; La Barbera, Daniele; Lasalvia, Antonio; Tosato, Sarah; Tarricone, Ilaria; D'Andrea, Giuseppe; Tortelli, Andrea; Schürhoff, Franck; Szöke, Andrei; Pignon, Baptiste; Selten, Jean-Paul; Velthorst, Eva; de Haan, Lieuwe; Llorca, Pierre-Michel; Rossi Menezes, Paulo; Del Ben, Cristina M; Santos, Jose Luis; Arrojo, Manuel; Bobes, Julio; Sanjuán, Julio; Bernardo, Miquel; Arango, Celso; Kirkbride, James B; Jones, Peter B; Richards, Alexander; Rutten, Bart P; Van Os, Jim; Austin-Zimmerman, Isabelle; Li, Zhikun; Morgan, Craig; Sham, Pak C; Vassos, Evangelos; Wong, Chloe; Bentall, Richard; Fisher, Helen L; Murray, Robin M; Alameda, Luis; Di Forti, Marta. (2023). Cannabis use as a potential mediator between childhood adversity and first-episode psychosis: results from the EU-GEI case-control study.. Psychological medicine, 53(15), 7375-7384. https://doi.org/10.1017/S0033291723000995