Antipsychotics and relapse risk in persons with first-episode psychosis and co-occurring cannabis use disorder

Wednesday, 23 October, 2024 - 15:00 to 16:30

Background

Cannabis use is associated with an increased relapse rate in persons with psychosis and in general, antipsychotic medications are effective in reducing relapses in psychosis. There is a lack of research on the effectiveness of antipsychotics regarding patients with concomitant cannabis use and psychosis, and regarding comparative effectiveness of specific antipsychotics. We aimed to study real-world effectiveness of antipsychotics for preventing psychosis relapses among persons with first-episode psychosis and co-occurring cannabis use disorder.  

Methods

Swedish nationwide registers were utilized to identify persons with first-episode psychosis and co-occurring cannabis use disorder (first-time diagnosis of psychosis as ICD-10 F20-F29, with concomitant recording of F12) during the years 2006-2021. Association between use of specific antipsychotics (oral vs. long-acting injectable, LAI, forms) and risk of hospitalization due to psychosis relapse was investigated in within-individual design where each person acts as his/her own control to minimize selection bias, analyzed with stratified Cox models. 

Results

The cohort of persons with first-episode psychosis and co-occurring cannabis use diorder included 1820 patients (85% men, mean age 26.8, SD 8.3). Of them, 81.9% used antipsychotics during the follow-up and 63.6% were re-recorded with a cannabis use-related diagnosis, indicating persistent use. During the follow-up, 61% (N=1111) of the cohort experienced psychosis relapse. Compared with non-use, use of any antipsychotic was associated with a 33% decreased risk of relapse (aHR 0.67, 95%CI 0.60-0.72). The lowest risk of relapse was found for risperidone-LAI (0.40, 0.22-0.71), aripiprazole-LAI (0.42, 0.27-0.65), clozapine (0.43, 0.29-0.64), paliperidone-LAI (0.46, 0.30-0.69) and antipsychotic polytherapy (0.60, 0.51-0.70). Of oral non-clozapine antipsychotics, aripiprazole was associated with the lowest risk of relapse (0.61, 0.45-0.83). 

Conclusions 

Antipsychotics are effective in relapse prevention in patients with first-episode psychosis and co-occurring cannabis use disorder. These findings support the use of long-acting injectable formulations of second-generation antipsychotics in relapse prevention in these patients.

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A7 23 1500 1 Heidi Taipale.pdf 605.82 KB Download

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