Study to Measure Drug Satisfaction of Patients With Schizophrenia After Switching From Risperidone to Paliperidone

Paliperidone ER has been shown to be effective compared to placebo ("a sugar pill") in the acute treatment and maintenance of patients with schizophrenia. Paliperidone ER combines an active metabolite of another antipsychotic, risperidone, with manufacturing technology allowing more gradual release of the drug and less difference in high and low blood levels of the drug. Side effects to medications are sometimes due to wide differences in these high and low blood levels. Recent research has shown that many patients with schizophrenia discontinue their antipsychotic medication due to "subject-choice". Therefore, it is important that research studies attempt to measure patients' satisfaction with antipsychotic medication, in addition to measuring how they respond on tests of effectiveness. This study has been designed to evaluate antipsychotic medication satisfaction in patients who continue to have symptoms of schizophrenia, and who say they are dissatisfied with their current risperidone treatment. The primary outcome is the change in the Medication Satisfaction Questionnaire (MSQ) score, from baseline to the Week 6 endpoint. These patients are randomized (like flipping a coin) as to when their risperidone (4 mg to 6 mg per day) is switched to paliperidone ER. Because the study is 'blinded', neither the study doctor nor the patient will know when treatment with risperidone is stopped and treatment with paliperidone ER begins. Throughout the study all patients continue to receive antipsychotic medication daily. Patients will continue on the same daily dose of risperidone until their randomly assigned switch to paliperidone ER. All patients will be switched to paliperidone ER over the course of study and once switched continue to take paliperidone ER for the remainder of the study. Paliperidone ER is started at 6 mg/day and can be increased to 9 mg/day or 12 mg/day at the doctor's discretion. Effectiveness and safety will be measured at visits scheduled weekly for the first four weeks and then at the Week 6 endpoint. At each visit, patients will be asked to complete psychiatric tests and questionnaires that will measure effectiveness and patient satisfaction with the medicine. They will also complete tests and evaluations for safety, including electrocardiograms (ECGs, electrical tracings of the heart) and blood samples at the beginning and end of the study. Each patient receives two blinded capsules by mouth once daily in the morning for 6 weeks. Patients taking risperidone receive either a 4-mg or 6-mg capsule plus a placebo capsule. When patients are switched, Paliperidone ER is started at 6 mg/day the day after risperidone is discontinued and can be increased to 9 mg/day or 12 mg/day at the doctor's discretion. Paliperidone 3-mg and 6-mg capsules are combined with placebo to equal the total dose in two capsules.