Environmental Risk Factors Linked to Cognitive Decline at First Psychosis Episode

First-episode psychosis patients with the most cognitive deterioration had higher cannabis exposure and more environmental risk factors than those who maintained cognitive function.

Ferraro, Laura et al.·Psychological medicine·2025·Moderate EvidenceCross-Sectional
RTHC-06450Cross SectionalModerate Evidence2025RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Cross-Sectional
Evidence
Moderate Evidence
Sample
N=205

What This Study Found

Among 802 first-episode psychosis patients, those in the "deteriorating" cognitive cluster had higher cannabis exposure than the "intermediate" cluster with identical IQ, and all patient clusters had higher environmental risk scores than the 1,263 community controls.

Key Numbers

802 FEP patients clustered into: high-functioning (n=205), low-functioning (n=223), intermediate (n=224), deteriorating (n=150). Deteriorating cluster had higher cannabis exposure than intermediate (mean difference=0.48, 95% CI 0.49-0.91). ERS highest in deteriorating cluster (beta=2.8, 95% CI 2.3-3.4).

How They Did This

Cross-sectional analysis from the EU-GEI study comparing cognitive clusters of 802 first-episode psychosis patients and 1,263 controls. Used the Maudsley Environmental Risk Score (ERS) combining paternal age, childhood adversities, cannabis use, and ethnic minority status.

Why This Research Matters

This study helps untangle why some people with psychosis experience cognitive decline while others maintain function. Cannabis exposure emerged as one distinguishing factor, separate from baseline intelligence.

The Bigger Picture

Identifying modifiable risk factors like cannabis use that contribute to cognitive deterioration in psychosis opens the door to targeted early interventions that could preserve cognitive function.

What This Study Doesn't Tell Us

Cross-sectional design cannot establish causation. Environmental risk score combines multiple factors. Cognitive clusters derived from single timepoint assessment. Cannabis exposure was one component of a composite score.

Questions This Raises

  • ?Would reducing cannabis exposure before psychosis onset prevent cognitive deterioration?
  • ?Are the cognitive trajectories reversible with intervention?

Trust & Context

Key Stat:
Deteriorating cluster had significantly higher cannabis exposure than same-IQ peers
Evidence Grade:
Large multi-site study (EU-GEI) but cross-sectional, limiting causal conclusions.
Study Age:
2025 study
Original Title:
Cognitive presentation at psychosis onset through premorbid deterioration and exposure to environmental risk factors.
Published In:
Psychological medicine, 55, e12 (2025)
Database ID:
RTHC-06450

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

A snapshot of a population at one point in time.

What do these levels mean? →

Frequently Asked Questions

What does "deteriorating cluster" mean?

Researchers grouped psychosis patients by cognitive patterns. The deteriorating cluster had cognitive function lower than expected based on their premorbid (pre-illness) abilities, suggesting decline associated with the illness.

Does this prove cannabis causes cognitive decline in psychosis?

No. The study found an association between higher cannabis exposure and cognitive deterioration, but the cross-sectional design cannot prove causation. Other factors may also contribute.

Read More on RethinkTHC

Cite This Study

RTHC-06450·https://rethinkthc.com/research/RTHC-06450

APA

Ferraro, Laura; Di Forti, Marta; La Barbera, Daniele; La Cascia, Caterina; Morgan, Craig; Tripoli, Giada; Jongsma, Hannah; Seminerio, Fabio; Sartorio, Crocettarachele; Sideli, Lucia; Tarricone, Ilaria; Carloni, Anna Lisa; Szoke, Andrei; Pignon, Baptiste; Bernardo, Miguel; de Haan, Lieuwe; Arango, Celso; Velthorst, Eva; Gayer-Anderson, Charlotte; Kirkbride, James; Rutten, Bart P F; Lasalvia, Antonio; Tosato, Sarah; Del Ben, Cristina Marta; Menezes, Paulo Rossi; Bobes, Julio; Arrojo, Manuel; Tortelli, Andrea; Jones, Peter; Selten, Jean-Paul; van Os, Jim; Murray, Robin; Quattrone, Diego; Vassos, Evangelos. (2025). Cognitive presentation at psychosis onset through premorbid deterioration and exposure to environmental risk factors.. Psychological medicine, 55, e12. https://doi.org/10.1017/S0033291724003507

MLA

Ferraro, Laura, et al. "Cognitive presentation at psychosis onset through premorbid deterioration and exposure to environmental risk factors.." Psychological medicine, 2025. https://doi.org/10.1017/S0033291724003507

RethinkTHC

RethinkTHC Research Database. "Cognitive presentation at psychosis onset through premorbid ..." RTHC-06450. Retrieved from https://rethinkthc.com/research/ferraro-2025-cognitive-presentation-at-psychosis

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.