A Study of the Effectiveness and Safety of Risperidone Compared With Haloperidol 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 five dosages of risperidone (1, 4, 8, 12, or 16 mg per day) compared with a fixed dose of a standard antipsychotic, haloperidol (10 mg per day) in patients with chronic schizophrenia. 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, and 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 percent of patients showing clinical improvement on the Positive and Negative Syndrome Scale for Schizophrenia (PANSS) and the average total PANSS score, from baseline to the 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, urinalysis, and hormone levels), 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 doses of 4, 8, 12, or 16 mg/day are more effective than risperidone 10 mg/day, as measured by clinical improvement on PANSS and the average total score for PANSS, in patients with chronic schizophrenia. Risperidone oral tablets, twice-daily, starting with 1 or 2 mg/day, increasing gradually in Week 1 (except for 1 mg/day group), then 0.5, 2, 4, 6, or 8 mg twice daily for 7 weeks. Haloperidol oral tablets, twice-daily, starting with 2 mg/day, increasing to 5 mg twice daily in Week 1, then 5 mg twice daily for 7 weeks.