Long-acting injectable risperidone was assessed in schizophrenia patients who were symptomatically stable on conventional depot antipsychotics and who were then switched to long-acting risperidone. Participants in this open-label, multicentre, 12-week trial had received flupenthixol decanoate, fluphenazine decanoate, haloperidol decanoate, or zuclopenthixol decanoate for 4 months or longer. Each was considered symptomatically stable by investigators. After receiving two cycles of their conventional depot antipsychotic during the run-in period, patients were switched to receive long-acting risperidone every 2 weeks for 12 weeks at an initial dose of 25 mg. This dose could be increased in 12.5-mg increments at 4-week intervals. Ninety-two percent of the patients received all six injections; 62% received the 25-mg dose throughout the treatment period. Adverse events related to movement disorders were reported in 3%. Severity of movement disorders decreased during long-acting risperidone treatment. Positive and Negative Syndrome Scale (PANSS) total and factor scores and scores on the Clinical Global Impressions severity scale were significantly reduced during treatment; 48% of these stable patients showed further symptom improvement (> or =20% decrease in PANSS score at endpoint). The results indicate that patients with schizophrenia who are symptomatically stable during treatment with a conventional depot antipsychotic can be safely and effectively switched to long-acting injectable risperidone without a prior transition to oral risperidone.