A Study to Evaluate the Efficacy and Safety of Adjustable Doses of Extended-release (ER) Paliperidone Compared With Placebo, in Combination With Lithium or Valproate, to Treat Manic and Mixed Episodes in Patients With Bipolar I Disorder

The purpose of this study is to evaluate the effectiveness and safety over a 6-week period of paliperidone ER compared with placebo in treating subjects with Bipolar I Disorder who are experiencing a manic or mixed episode while they are taking lithium or valproate. This study will also evaluate the effect of paliperidone ER compared with placebo on overall functioning, on how quickly a response is seen, on improvement in severity of illness, on health-related functional status, on depressive symptoms, and on psychotic symptoms. The relationship between blood levels and the effectiveness and safety of paliperidone ER will be evaluated, including the effect of food relative to time of taking the drug.