Inclusion Criteria:

• subjects must have bipolar I, II or NOS disorder as defined by DSM-IV-TR; must have clinical significant depressive symptoms and have failed one or more mood stabilizer trials; may or may not be receiving antimanic or mood stabilizing medications; subjects or legally authorized representative must sign the Informed Consent document after the nature of the trial has been fully explained; if female, subjects must be postmenopausal, surgically incapable of childbearing or practicing medically acceptable effective method(s) of contraception.

Exclusion Criteria:

• subjects who do not have bipolar disorder by DSM-IV criteria; subjects with current DSM-IV Axis I diagnosis of delirium, dementia, amnesia or other cognitive disorders or a psychotic disorder; subjects with serious general medical illness; subjects who are allergic to or have demonstrated hypersensitivity to aripiprazole; women who are pregnant or nursing; subjects who have received an experimental drug or used an experimental device within 30 days; subjects who have a history of neurologic malignant syndrome.