Does lack of improvement in the first two weeks predict treatment resistance in recent-onset psychosis?

Abstract

Randomized controlled trials among patients with schizophrenia have shown that <20% improvement in the first two weeks of treatment predicts nonresponse after 12 weeks. The findings have been consistent for patients treated with both conventional (1) and second-generation antipsychotic (AP) drugs (2). However, despite the lack of evidence regarding the length of time that clinicians should pursue one treatment regimen, most psychiatric textbooks and practice guidelines suggest that patients should be treated for at least four to six weeks with one AP (3-5) before switching to another (6). Large pragmatic trials with chronic patients, such as the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) (7), have found no benefit from switching AP drugs (8,9). No studies have considered less chronic patients, such as patients with recent-onset schizophrenia (i.e., less than five years of illness duration). We investigated responses to APs and switching strategies in patients with recent-onset schizophrenia. We used the IPAP algorithm, which is a well-defined algorithm for treating schizophrenia (4,10).