Rationale: Discontinuation of antipsychotic treatment at early phases increases the risk of poor adherence to maintenance drug therapy. Differences among antipsychotics in terms of effectiveness may determine a good adherence to treatment.
Objectives: The aim of this study is to compare the clinical effectiveness of aripiprazole, ziprasidone and quetiapine in the treatment of first-episode schizophrenia spectrum disorders at 1 year.
Method: From October 2005 to January 2011 a prospective, randomized, open-label study was undertaken. Two hundred two first-episode drug-naïve patients were randomly assigned to aripiprazole (N = 78), ziprasidone (N = 62), or quetiapine (N = 62) and followed up for 1 year. The primary effectiveness measure was all-cause of treatment discontinuation. In addition, an analysis based on intention-to-treat principle was conducted in the analysis for clinical efficacy.
Results: The overall dropout rate at 1 year was 13.37 %. The treatment discontinuation rate differed significantly between treatment groups (aripiprazole = 43.6 %, ziprasidone = 66.1 % and quetiapine = 82.3 %) (χ 2 = 22.545; p < 0.001). Insufficient efficacy in the group of quetiapine is the most important reason for differences in discontinuation rates between agents (χ 2 = 19.436; p < 0.001). The mean time to all-cause discontinuation was significantly different between groups (LogRank = 30.732 p < 0.001). The profile of extrapyramidal symptoms varies between treatments. Patients on ziprasidone were more likely to be prescribed antidepressants.
Conclusions: First episode patients treated with quetiapine have a higher risk of treatment discontinuation at midterm due to insufficient efficacy. Establishing differences between SGAs may help clinicians on prescribing decision for treatment of individuals presenting with first-episode non-affective psychosis.