Does cannabis use worsen dissociation and functioning in first-episode psychosis over time? | Research

The takeaway

A prospective study of 70 first-episode psychosis patients found that those with cannabis use disorder had higher dissociative symptoms and worse functioning that persisted at 8 months, while non-users' functioning improved over the same period.

Clinicians managing first-episode psychosis in cannabis users, and researchers interested in how dissociative symptoms interact with psychosis and substance use.

Cannabis users: functioning worsened; non-users: improved

What the researchers found

Cannabis-using FEP patients showed higher positive symptoms, higher dissociative experiences (DES-II), and worse functioning (GAF) than non-users at onset. At 8-month follow-up, cannabis users still had elevated positive symptoms and dissociation. Functioning worsened over time in cannabis users while improving in non-users, despite comparable antipsychotic treatment.

Why it matters

The divergent trajectory of functioning (worsening with cannabis use, improving without) is particularly concerning. It suggests cannabis use during first-episode psychosis actively undermines recovery rather than just being a marker of worse prognosis.

The numbers in context

70 patients (35 CUD, 35 non-CUD); cannabis users had higher positive symptoms, dissociation, and worse functioning at baseline; at 8 months: positive symptoms and dissociation still elevated in cannabis group; functioning worsened in cannabis group vs improved in non-cannabis group

How the study worked

Prospective cohort study of 70 first-episode psychosis patients (35 with CUD, 35 without) recruited from Italian psychiatric inpatient facilities (2014-2019). Assessed at FEP onset, 4 months, and 8 months using PANSS, GAF, and DES-II.

What this study cannot tell us

Small sample (35 per group). Italian inpatient population may not generalize. Cannot determine if cannabis caused the worse trajectory or if patients with worse prognosis are more likely to continue using cannabis.

How to read the evidence

Prospective design with 8-month follow-up and matched comparison group, but small sample and potential confounding.

When this study was published

Published in 2021; the role of dissociation in cannabis-associated psychosis is gaining research attention.

The bigger picture

The dissociative component of cannabis-associated psychosis is often overlooked. If cannabis promotes both psychotic and dissociative symptoms while undermining functional recovery, it represents a more complex clinical problem than simply managing hallucinations and delusions.

Questions still open

Does cannabis cessation reverse the functional decline? Is dissociation a mediator between cannabis use and poor psychosis outcomes? Would specifically targeting dissociation in treatment improve outcomes for cannabis-using psychosis patients?

Common questions

What is dissociation in psychosis?

Dissociation involves feeling disconnected from reality, one's body, or one's thoughts. This study found cannabis-using psychosis patients experienced more dissociative symptoms than non-users, which persisted over 8 months.

Does cannabis prevent recovery from psychosis?

In this study, patients with cannabis use disorder saw their functioning worsen over 8 months while non-users improved, despite receiving similar antipsychotic treatment. This suggests cannabis may actively interfere with recovery.

Read the original research

Cannabis use disorder and dissociation: A report from a prospective first-episode psychosis study.

Drug and alcohol dependence, 229(Pt A), 109118

View on PubMed ↗Publisher’s paper ↗

Citation

Ricci, V; Ceci, F; Di Carlo, F; Lalli, A; Ciavoni, L; Mosca, A; Sepede, G; Salone, A; Quattrone, D; Fraticelli, S; Maina, G; Martinotti, G. (2021). Cannabis use disorder and dissociation: A report from a prospective first-episode psychosis study.. Drug and alcohol dependence, 229(Pt A), 109118. https://doi.org/10.1016/j.drugalcdep.2021.109118