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

The takeaway

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.

Psychosis patients who use cannabis, their families, psychiatrists, and early intervention program designers.

Ex-users matched never-users on all outcomes at 10 years

What the researchers 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.

Why it 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 numbers in context

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 the study worked

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.

What this study cannot 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.

How to read the evidence

Strong: 10-year longitudinal follow-up of a well-characterized first-episode psychosis cohort with clear clinical endpoints.

When this study was published

Published in 2019.

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.

Questions still open

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?

Common 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.

Read the original research

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

View on PubMed ↗Publisher’s paper ↗

Citation

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