Continuing Cannabis After First Psychosis Led to Worse Depression, More Psychotic Symptoms, and Higher Suicide Risk

Among 44 patients (22 cannabis users, 22 non-users) followed for 9 months after cannabis-induced FEP, continued cannabis users had persistently higher depression scores (p=0.0000001 at 9 months), suicidality (p<0.001), and PANSS positive scores (p<0.0002) compared to those who stopped. Cannabis users had higher relapse rates (59.9% vs 18.8%). GAF scores improved significantly only in the non-user group (p=0.024). Both groups showed some positive symptom improvement, but cannabis users recovered more slowly.

Prospective cohort of 65 patients aged 16-50 with cannabis-induced first-episode psychosis from psychiatric inpatient facilities in northern Italy. Categorized by cannabis use during 9-month follow-up. 44 completed the study (NCU=22, CU=22). Assessed at baseline, 3, and 9 months using PANSS, CDSS, SSI, and GAF scales.

This study provides direct evidence of the consequences of continued cannabis use after a cannabis-induced psychotic episode. The dramatically worse outcomes across every measured domain, depression, suicidality, psychosis, and functioning, make a compelling clinical case for cannabis cessation as a first-line intervention in this population.

The scale of outcome differences between those who continued vs stopped cannabis is striking. This is not a subtle effect: depression, suicidality, and relapse rates were dramatically worse in continued users. This evidence should inform clinical conversations about cannabis cessation after psychotic episodes.

Small sample (N=44). High dropout rate (32.3%). Non-randomized groups may differ in ways beyond cannabis use. Northern Italian sample. Cannot determine whether worse outcomes are caused by cannabis or whether sicker patients are less able to stop using.