Patients who quit cannabis after first-episode psychosis had outcomes similar to never-users at 10 years

Q: Does quitting cannabis actually reverse the damage?

This study found that people who quit cannabis had outcomes similar to those who never used at the 10-year mark. While "reverse" may be too strong (we don't know the mechanism), the clinical outcomes were equivalent.

Q: Why do some patients keep using despite worse outcomes?

Cannabis use in psychosis is complex. Patients may use for symptom relief, social reasons, or addiction. The finding that persistent users are more dissatisfied with medication suggests it may partly be a treatment engagement issue.

In a 10-year follow-up of first-episode psychosis patients, those who continued using cannabis had worse symptoms and functioning, while those who quit had outcomes indistinguishable from those who never used.

Setién-Suero, E et al.·Acta psychiatrica Scandinavica·2019·Strong EvidenceLongitudinal Cohort

Psychosis (531)Quitting (221)

Quick Facts

Study Type

Longitudinal Cohort

Evidence

Strong Evidence

Sample

Not reported

What This Study Found

Persistent cannabis users had more severe symptoms (BPRS: p < .001; SAPS: p = .002) and poorer functioning (DAS: p = .048; GAF: p = .033) at 10 years compared to ex-users and never-users. Ex-users showed a similar pattern to never-users on all measures.

Key Numbers

209 FEP patients followed for 10 years. Persistent users: worse BPRS (p < .001), SAPS (p = .002), DAS (p = .048), GAF (p = .033). Ex-users indistinguishable from never-users.

How They Did This

Longitudinal study of 209 first-episode psychosis patients from the PAFIP cohort, divided into persistent users, ex-users, and never-users. Clinical, functional, and cognitive outcomes assessed at baseline and 10-year follow-up.

Why This Research Matters

This is one of the longest follow-up studies to show that quitting cannabis after a first psychotic episode can essentially normalize outcomes. The message is clear: it is never too late to benefit from quitting.

The Bigger Picture

The reversibility of cannabis-related harm in psychosis is a powerful clinical message. Rather than viewing continued cannabis use as inevitable, this data supports aggressive cessation interventions early in the course of psychosis.

What This Study Doesn't Tell Us

Observational design; self-selected quitters may differ from persistent users in ways not captured. Cannabis use assessed by self-report. Specific consumption patterns and potency were not detailed.

Questions This Raises

?How soon after quitting do outcomes begin to improve?
?Does it matter when in the course of illness cessation occurs?
?What cessation interventions are most effective for psychosis patients?

Trust & Context

Key Stat:: Ex-users matched never-users on all outcomes at 10 years
Evidence Grade:: Strong: 10-year longitudinal follow-up of a well-characterized first-episode psychosis cohort with clear clinical endpoints.
Study Age:: Published in 2019.
Original Title:: Stopping cannabis use benefits outcome in psychosis: findings from 10-year follow-up study in the PAFIP-cohort.
Published In:: Acta psychiatrica Scandinavica, 140(4), 349-359 (2019)
Authors:: Setién-Suero, E, Neergaard, K, Ortiz-García de la Foz, V, Suárez-Pinilla, P, Martínez-García, O, Crespo-Facorro, B, Ayesa-Arriola, R
Database ID:: RTHC-02289

Evidence Hierarchy

Meta-Analysis / Systematic Review

Randomized Controlled Trial

Cohort / Case-ControlFollows or compares groups over time

This study

Cross-Sectional / Observational

Case Report / Animal Study

Follows a group of people over time to track how outcomes develop.

What do these levels mean? →

Frequently Asked Questions

Does quitting cannabis actually reverse the damage?

This study found that people who quit cannabis had outcomes similar to those who never used at the 10-year mark. While "reverse" may be too strong (we don't know the mechanism), the clinical outcomes were equivalent.

Why do some patients keep using despite worse outcomes?

Cannabis use in psychosis is complex. Patients may use for symptom relief, social reasons, or addiction. The finding that persistent users are more dissatisfied with medication suggests it may partly be a treatment engagement issue.

Cite This Study

RTHC-02289·https://rethinkthc.com/research/RTHC-02289

APA

Setién-Suero, E; Neergaard, K; Ortiz-García de la Foz, V; Suárez-Pinilla, P; Martínez-García, O; Crespo-Facorro, B; Ayesa-Arriola, R. (2019). Stopping cannabis use benefits outcome in psychosis: findings from 10-year follow-up study in the PAFIP-cohort.. Acta psychiatrica Scandinavica, 140(4), 349-359. https://doi.org/10.1111/acps.13081

MLA

Setién-Suero, E, et al. "Stopping cannabis use benefits outcome in psychosis: findings from 10-year follow-up study in the PAFIP-cohort.." Acta psychiatrica Scandinavica, 2019. https://doi.org/10.1111/acps.13081

RethinkTHC

RethinkTHC Research Database. "Stopping cannabis use benefits outcome in psychosis: finding..." RTHC-02289. Retrieved from https://rethinkthc.com/research/setien-suero-2019-stopping-cannabis-use-benefits

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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.

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