Long-Term Real-World Effectiveness of Pharmacotherapies for Schizoaffective Disorder

Objective: To investigate the long-term real-world effectiveness of antipsychotics and other psychopharmacotherapies in the treatment of schizoaffective disorder (SCHAFF).

Method: Two nationwide cohorts of SCHAFF patients were identified from Finnish and Swedish registers. Within-individual design was used with stratified Cox regression. The main exposure was use of antipsychotics. Adjunctive pharmacotherapies included mood stabilizers, antidepressants, and benzodiazepines and benzodiazepine-related drugs. The main outcome was hospitalization due to psychosis.

Results: The Finnish cohort included 7655 and the Swedish cohort 7525 patients. Median follow-up time was 11.2 years (IQR 5.6-11.5) in the Finnish and 7.6 years (IQR 3.8-10.3) in the Swedish cohort. Clozapine and long-acting injectable (LAI) antipsychotics were consistently associated with a decreased risk of psychosis hospitalization and treatment failure (psychiatric hospitalization, any change in medication, death) in both cohorts. Quetiapine was not associated with a decreased risk of psychosis hospitalization. Mood stabilizers used in combination with antipsychotics were associated with a decreased risk of psychosis hospitalization (Finnish cohort HR 0.76, 95% CI 0.71-0.81; Swedish cohort HR 0.84, 0.78-0.90) when compared with antipsychotic monotherapy. Combination of antidepressants and antipsychotics was associated with a decreased risk of psychosis hospitalization in the Swedish cohort (HR 0.90, 0.83-0.97) but not in the Finnish cohort (1.00, 0.94-1.07), and benzodiazepine use was associated with an increased risk (Finnish cohort HR 1.07, 1.01-1.14; Swedish cohort 1.21, 1.13-1.30).

Conclusions: Clozapine, LAIs, and combination therapy with mood stabilizers were associated with the best outcome and use of quetiapine and benzodiazepines with the worst outcome in the treatment of SCHAFF.