Quetiapine in schizophrenia: onset of action within the first week of treatment

OBJECTIVE: Three placebo-controlled clinical trials have established the efficacy of the atypical antipsychotic quetiapine (Seroquel) in schizophrenia. These trials were designed and powered to detect a treatment difference in the primary endpoint at Week 6. The objective of the current analysis was to investigate the effect of quetiapine at earlier timepoints. RESEARCH DESIGN AND METHODS: A combined analysis of data from three acute, double-blind, placebo-controlled, randomised trials was carried out. The trials comprised hospitalised patients with an acute exacerbation of chronic or subchronic schizophrenia who were randomised to receive quetiapine 150-750 mg/day (n = 422) or placebo (n = 198). Symptoms were assessed using changes from baseline to Week 1 in the Brief Psychiatric Rating Scale (BPRS) total score, BPRS positive symptom cluster score and the individual BPRS items of excitement, tension and depression. Changes from baseline to Weeks 1-6 were calculated for BPRS Factor 1 scores (which measures mood symptoms) and Scale for Assessment of Negative Symptoms (SANS) summary scores. RESULTS: Within 1 week, overall symptom improvement (BPRS total score) was significantly (p < 0.05) greater with quetiapine than with placebo; improvement also occurred in individual BPRS items of excitement, tension and depression. Improvement in negative symptoms was significantly (p < 0.05) greater with quetiapine than with placebo from Week 1, as was the BPRS Factor I score from Week 2. More quetiapine- than placebo-treated patients showed a response of positive symptoms to treatment within 1 week (p < 0.05). CONCLUSIONS: The beneficial effects of quetiapine are observed within 1 week across a broad spectrum of symptoms.