The primary hypothesis for this study is that, during the long-term treatment of patients with Bipolar I Disorder who maintain clinical stability after an acute manic or mixed episode, ER paliperidone is superior to placebo in delaying the time to recurrence of any mood symptoms associated with Bipolar I Disorder. Patients begin the acute treatment phase at 6.0 mg/day of oral ER paliperidone or 10 mg/day of oral olanzapine. Dosages may be adjusted, as needed, between 3 to 12 mg/day of ER paliperidone or 5 to 20 mg/day of olanzapine, through the end of the continuation phase. Then, in the maintenance phase, patients receive the dosage of ER paliperidone (or ER paliperidone placebo) or olanzapine reached at the end of the continuation phase. They remain on those dosages until the end of the study.