A Study of the Effectiveness and Safety of Risperidone Compared With Haloperidol and Placebo in Patients With Chronic Schizophrenia

Chronic schizophrenia is a longer-term condition that is characterized by a lack of drive, underactivity and slowness, and social withdrawal. As with the acute form of schizophrenia, delusions and hallucinations are common. This is a randomized, double-blind, parallel-group study to evaluate the effectiveness and safety of four dosages of risperidone (2, 6, 10 or 16 mg/day) compared with placebo and with a fixed 20 mg/day dose of a standard antipsychotic, haloperidol in patients with chronic schizophrenia who are in-patients at the beginning of the study. The study is composed of two phases: a 1-week period, in which patients receive placebo and all current medication for schizophrenia treatment is stopped, followed by a double-blind treatment phase. The doses of study drug are increased progressively during the first week of the double-blind period and then remain constant for the next 7 weeks. The primary measures of effectiveness are the percentage of patients showing clinical improvement (reduction of \>=20% from baseline) on the Positive and Negative Syndrome Scale for Schizophrenia (PANSS) and the total PANSS score, from baseline to end of double-blind treatment. The PANSS is a rating scale that measures the symptoms of schizophrenia. Safety evaluations include the incidence of adverse events, results of clinical laboratory tests (hematology, biochemistry, and urinalysis), plasma levels of risperidone, measurements of vital signs and body weight, physical examination and electrocardiogram (ECG) findings, neurological examinations, and the Extrapyramidal Symptoms Rating Scale (ESRS), a scale used to measure effects of antipsychotic medications on motor functions of the patient. The study hypothesis is that risperidone is more effective than placebo, as measured by clinical improvement on PANSS and the average total score for PANSS, in patients with chronic schizophrenia. Risperidone tablets, taken orally, starting with 1 mg twice daily, gradually increasing dose in Week 1 (except for 1 mg twice daily group), then 1, 3, 5, or 8 mg twice daily, continuing for 7 weeks. Haloperidol tablets, starting 1 mg twice daily and increasing to 10 mg twice daily (Week 1), continuing 10 mg twice daily for 7 weeks.