Psychosis in medical conditions: response to risperidone.

We report the response to risperidone in seven hospitalized, adult patients who presented psychotic symptoms etiologically related to a general medical condition. The conditions included brain surgery in two, and anticardiolipin syndrome, renal failure, epilepsy, lupus, and metastatic carcinoma in one each. Four patients had failed previous treatment with at least one typical antipsychotic agent. Response to risperidone was assessed by the Brief Psychiatric Rating Scale (BPRS). Serum was collected for measurement of steady-state trough risperidone and 9-hydroxyrisperidone concentrations at effective doses in three patients. Amelioration of psychotic symptoms was noted in all seven patients. Mean (+/- SD) BPRS scores were reduced significantly from baseline (63.0 +/- 15.1) to endpoint (27.0 +/- 3.5; p < 0.01). The mean effective daily dose of risperidone was 3.1 +/- .7 mg and time to response was 4.7 +/- 2.4 days. Risperidone was not present at detectable concentrations in the three patients studied. The mean steady-state trough serum concentration of 9-hydroxyrisperidone in the three patients assessed was 20.3 +/- 9.8 ng/ml. These preliminary findings, which suggest that risperidone is a safe and effective agent in patients with psychotic symptoms due to various medical conditions, need to be confirmed by randomized, antipsychotic comparison trials involving a larger number of patients.