Change in cannabis use, clinical symptoms and social functioning among patients with first-episode psychosis: a 5-year follow-up study of patients in the OPUS trial.

BACKGROUND: Several studies indicate that cannabis use among patients with psychotic disorders is associated with worse outcome, but only a few studies have controlled for baseline condition and medication. METHOD: At 5-year follow-up, interviews were carried out with 314 first-episode psychosis patients included in the OPUS trial. The patients included were in the age range of 18 to 45 years old and 59% were male. Cannabis use was extracted from the Schedule for Clinical Assessment in Neuropsychiatry. At follow-up, the patients were divided into different groups according to the variable cannabis use: abstainers, stoppers, starters and continuers. Psychotic, negative and disorganized dimensions (ranging from zero to five) were calculated for each of the four groups based on the Schedule for the Assessment of Positive and Negative Symptoms in Schizophrenia. RESULTS: Cannabis users were younger (24.6 years v. 27.4 years, p < 0.001) and had a lower level of education. At the 5-year follow-up, users of cannabis had higher scores on the psychotic dimension [difference 0.97, 95% confidence interval (CI) 0.41-1.53, p = 0.001] and lower levels of the Global Assessment of Functioning (difference 8.26, 95% CI 2.13-14.39, p = 0.01). Those who stopped using cannabis between entry and 5-year follow-up had a significantly lower level of psychotic symptoms at 5-year follow-up even after controlling for baseline level of psychotic symptoms and for insufficient antipsychotic medication (adjusted difference in psychotic dimension -1.04, 95% CI -1.77 to -0.31, p = 0.006). CONCLUSIONS: Continuous cannabis use was associated with higher levels of psychotic symptoms after 5 years, and this association was only partly explained by insufficient antipsychotic medication.

Specialized psychosocial treatment plus treatment as usual (TAU) versus TAU for patients with cannabis use disorder and psychosis: the CapOpus randomized trial.

BACKGROUND: Cannabis abuse in psychotic patients is associated with rehospitalizations, reduced adherence and increased symptom severity. Previous psychosocial interventions have been ineffective in cannabis use, possibly because of low sample sizes and short interventions. We investigated whether adding CapOpus to treatment as usual (TAU) reduces cannabis use in patients with cannabis use disorder and psychosis. Method A total of 103 patients with psychosis and cannabis use disorder were centrally randomized to 6 months of CapOpus plus TAU (n = 52) or TAU (n = 51). CapOpus consisted mainly of motivational interviewing and cognitive behaviour therapy (CBT). TAU was targeted primarily at the psychotic disorder. The primary outcome was self-reported days with cannabis use in the preceding month. RESULTS: Pre-randomization cannabis use frequency was 14.9 [95% confidence interval (CI) 12.7-17.1] days/month. Post-treatment, the ratio of days/month with cannabis use in CapOpus versus TAU was 0.76 (95% CI 0.38-1.50) (p = 0.42), and 0.80 (95% CI 0.21-3.10) (p = 0.75) at the 4-month follow-up. From 46.4 (95% CI 36.4-56.3) monthly joints pre-randomization, consumption fell to 27.3 (95% CI 12.6-41.9) joints in CapOpus and 48.2 (95% CI 31.8-64.6) in TAU (p = 0.06). Follow-up amounts were 28.4 (95% CI 13.5-43.2) and 41.6 (95% CI 25.2-58.0) joints (p = 0.23). Several subgroup analyses suggested benefits of CapOpus. CONCLUSIONS: CapOpus did not reduce the frequency, but possibly the amount, of cannabis use. This is similar to the findings of previous trials in this population. Implementation of CapOpus-type interventions is thus not warranted at present but subgroup analyses call for further trials.