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

The takeaway

Among 44 patients followed after cannabis-induced first-episode psychosis, those who continued using cannabis had persistently higher depression, suicidality, and psychotic symptoms with worse functional recovery.

Psychiatrists treating first-episode psychosis, patients who have experienced psychotic episodes, families supporting recovery.

59.9% relapse with continued use vs 18.8% without

What the researchers found

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.

Why it matters

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 numbers in context

44 patients (22 per group). 9-month follow-up. Depression: CU significantly higher at 3 and 9 months. Suicidality: CU significantly higher at both timepoints. Relapse: 59.9% CU vs 18.8% NCU. GAF improved only in NCU (p=0.024). PANSS positive: CU higher at all timepoints.

How the study worked

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.

What this study cannot tell us

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.

How to read the evidence

Moderate: prospective design with multiple validated assessments, though small sample and potential selection bias.

When this study was published

2025 study

The bigger picture

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.

Questions still open

What interventions best help psychosis patients stop using cannabis? Is there a time window after FEP where cessation produces the best outcomes? Would CBD supplementation help patients who cannot stop cannabis entirely?

Common questions

What happens if you keep using cannabis after a psychotic episode?

This study found dramatically worse outcomes: higher depression, more suicidal thoughts, 3 times more relapses, and no functional improvement compared to those who stopped. Both groups improved somewhat, but cannabis users recovered much more slowly.

Can you recover from cannabis-induced psychosis?

Yes, especially if you stop using cannabis. In this study, patients who stopped cannabis after their first psychotic episode showed significant improvement in function and lower relapse rates (18.8% vs 59.9% for continued users).

Read the original research

Effects of persistent cannabis use on depression, psychosis, and suicidality following cannabis-induced psychosis: A longitudinal study.

The American journal on addictions, 34(5), 547-557

View on PubMed ↗Publisher’s paper ↗

Citation

Ricci, Valerio; De Berardis, Domenico; Martinotti, Giovanni; Maina, Giuseppe. (2025). Effects of persistent cannabis use on depression, psychosis, and suicidality following cannabis-induced psychosis: A longitudinal study.. The American journal on addictions, 34(5), 547-557. https://doi.org/10.1111/ajad.70048