The primary objective of this study is to evaluate the amelioration of the sleep architecture of patients with schizophrenia and schizophrenia-related insomnia, treated with either 9 mg of extended-release paliperidone ER or placebo, using polysomnography.

Paliperidone is the major active substance produced by the metabolism of risperidone in the body. In patients with schizophrenia, risperidone has been shown to improve the quality of sleep. Therefore it is possible that treatment of paliperidone may improve sleep quality and potentially the quality of life in these patients. The goal of this study is to test the hypothesis that paliperidone improves sleep architecture. This trial is a multicenter, double-blind (neither the patient nor the physician will know if placebo or drug is being given and at what dose), randomized (patients will be assigned to different treatment groups based solely on chance), placebo-controlled study in patients with schizophrenia and schizophrenia related insomnia. The study consists of 2 phases: a screening phase of up to 14 days and a double-blind phase of 15 days. The primary purpose of this study is to evaluate improvement of the sleep architecture of patients with schizophrenia and schizophrenia-related insomnia, treated with either 9 mg/day of paliperidone ER or placebo for 14 days, using polysomnography. In this study, polysomnography (polygraphic recording during sleep of multiple body functions related to the state and stages of sleep to assess possible biological causes of sleep disorders) will be used to measure sleep architecture and continuity. Measurements will be taken on 2 days during the screening phase (averaged for the baseline value) and on the last 2 days of the treatment phase (averaged for the end point value) and will include measurement of non-rapid eye movement (NREM) sleep (including the 4 stages of sleep) and measures of rapid eye movement (REM) sleep. Other assessments pertinent to the continuity and efficiency of sleep such as sleep latency (the length of time that it takes to go from full wakefulness to Stage 2 sleep), sleep efficiency (proportion of sleep during time in bed), sleep maintenance (period of time between sleep onset and awakening and number of awakenings), and sleep duration (total sleep time) will also be measured. At baseline, on Day 7, and at end of treatment, the Positive and Negative Syndrome Scale (PANSS) will be used to assess the symptoms of schizophrenia and the Clinical Global Impression Scale - Severity (CGI-S) will be used to assess the severity of a patients condition. Safety assessments include the incidence of adverse events throughout the study; daily measurement of vital signs (blood pressure, pulse, and temperature); clinical laboratory tests performed both before the study initiation and at end of treatment; and measurement of extrapyramidal symptoms using scales (EPS scales) at baseline, Day 7 and end point. 9 mg of paliperidone ER or placebo taken orally once daily on Days 1 to 14

Inclusion Criteria:

• Diagnosed with schizophrenia and schizophrenia-related insomnia, no relapse or psychosis for at least 3 months before screening, and considered symptomatically stable
• have apnea/hypopnea score <10 and periodic leg movement score with an arousal index <10
• Weigh >/= 50 kg (>/=110 lbs), with a BMI >/= 18 and \