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

Abstract

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.