A trial of low doses of risperidone in the treatment of patients with first-episode schizophrenia, schizophreniform disorder, or schizoaffective disorder.

This UK multicenter, noncomparative, open-trial study assessed risperidone in 74 first-psychotic-episode patients (DSM-IV schizophrenia) treated with flexible doses. Treatment commenced at 1 mg/day, increasing to 2 mg after 3 days; then adjusted to 8 mg/day maximum. Treatment duration was 12 weeks (Phase 1) with follow-up of 62 patients to 1 year on risperidone or another antipsychotic (Phase 2). Superiority over baseline was recorded on all Positive and Negative Syndrome Scale (PANSS) subscale scores at week 12 (P < 0.0001), occurring after 3 days of treatment. Clinical Global Impression of Severity of Illness and Improvement (CGI-Severity) significantly improved over Phase 1 (80% of patients improved, 1% deteriorated). Treatment was considered from being very to quite acceptable in 79% and a success in 77% (P = 0.0001). Only 5 patients switched to another antipsychotic. Significant improvements were maintained to 1 year. Treatment-related adverse events reported by > 10% of patients in Phase 1 were somnolence (23%) and fatigue (10.8%). Five patients stopped risperidone due to adverse events. Nine patients reported that adverse events started in Phase 2, and 3 patients stopped risperidone. Twenty-one patients (28%) in Phase 1 and 4 patients (6%) in Phase 2 (including a patient taking thioridazine) reported extrapyramidal symptoms (EPS); none stopped treatment. There was no significant change in Abnormal Involuntary Movement Scale (AIMS) or Targeting Abnormal Kinetic Effects (TAKE) scale at 12 weeks. No significant change in AIMS and a significant improvement in TAKE scale were found from week 12 to 1 year. There was no significant difference in efficacy and tolerability between 1- to 4-mg/day and 5- to 8-mg/day dose groups in Phase 1 or 2. Low-dose risperidone is concluded to be effective and well tolerated in first episode psychosis. Only 2 patients (3%) required doses of over 6 mg/day.