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

Objective: 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.

Methods: 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.

Results: 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).

Conclusion: 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.