How long to wait before reducing antipsychotic dosage in stabilized patients with schizophrenia? A retrospective...

Antipsychotic dose reduction is generally recommended to occur after six months of clinical stabilization despite inadequate evidence. This timing issue was addressed in this study.

This is an observational, retrospective and medical chart-based study. Inclusion criteria were (1) diagnosis of schizophrenia (DSM-IV), (2) being acutely psychotic at their first outpatient visit from May, 2002 to April, 2003, (3) having responded to antipsychotics and achieved clinical stabilization of acute symptoms, indexed as a fixation of regimen for four or more weeks, and (4) having one or more years of follow-up. Patients who had their antipsychotic doses reduced were then identified, and they were divided into two groups based on the waiting period before dose reduction: <24 weeks (Early Group) and ≥24 weeks (Standard Group). The rate of dose escalation for ≥20% during follow-up period was investigated as a proxy of clinical worsening.

After excluding stable patients at baseline, 211 patients met inclusion criteria. The mean ± SD waiting period before reducing antipsychotics was 122 ± 102 days. The rates of patients needing dose escalation were not significantly different between patients whose dose was reduced (N = 83) and those who was not (N = 128) (57.8% vs. 59.4%), and between Early Group (N = 59) and Standard Group (N = 24) (61.0% vs. 50.0%) although the reduction rate in antipsychotic dosage was significantly greater in Early Group (58.7% vs. 43.3%, p < 0.05).

These findings may indicate that timeline until antipsychotic reduction in stable patients with schizophrenia could be earlier than recommended, although caution is needed in interpreting our retrospective results.