Study of Quetiapine Monotherapy in Ambulatory Bipolar Spectrum Disorder With Moderate-to-Severe Hypomanic Symptoms or Mild Manic Symptoms

1. Subjects must be 18 years of age or older.
2. Subjects must have bipolar I, II, or not otherwise specified (NOS) disorder as defined by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria. Of note, bipolar NOS disorder will include subjects with either recurrent or sporadic brief hypomanias (hypomanias of 1 to 3 days in duration).
3. Subjects must have moderate-to-severe hypomanic symptoms or mild manic symptoms that must be clinically significant (at least mild) but no worse than moderately severe, defined as a CGI-BP scale for mania > 3 and \< 5, on at least 2 assessment days at least 3 days apart during the screening phase.
4. Subjects must not be receiving mood stabilizing, antidepressant, or antipsychotic medication for > one week.
5. Subjects or their legally authorized representative must sign the Informed Consent document after the nature of the trial has been fully explained.
6. If female, subjects must be: postmenopausal, surgically incapable of childbearing, or practicing medically acceptable, effective method(s) of contraception (e.g., hormonal methods, intrauterine device) for at least one month prior to study entry and throughout the study.

Exclusion Criteria:

Criteria for exclusion from this study will be any of the following:

1. Subjects who do not have bipolar disorder by DSM-IV-TR criteria.
2. Subjects who are receiving treatment with an antimanic or mood stabilizing medication (lithium, valproate, carbamazepine, or an antipsychotic), and in the investigators' judgment, require ongoing treatment with that medication.
3. Subjects whose bipolar manic symptoms are presently less than mild (CGI-BP \< 2) or more than markedly ill (CGI-BP > 5 or YMRS > 21)
4. Subjects who have severe depressive symptoms (IDS > 39 ) or psychotic features (as defined in DSM-IV)
5. Subjects with clinically significant suicidal or homicidal ideation.
6. Subjects with a current DSM-IV Axis I diagnosis of delirium, dementia, amnesia, or other cognitive disorders; a DSM-IV diagnosis of a substance use disorder within the past six months; a lifetime DSM-IV psychotic disorder (e.g., schizophrenia or schizoaffective disorder).
7. Subjects with serious general medical illnesses including hepatic, renal, respiratory, cardiovascular, endocrine, neurologic, or hematologic disease as determined by the clinical judgment of the clinical investigator. Subjects with hypo- or hyperthyroidism unless stabilized on thyroid replacement > 3 months.
8. Subjects who are allergic to or who have demonstrated hypersensitivity to quetiapine.
9. Women who are pregnant or nursing.
10. Subjects who have received an experimental drug or used an experimental device within 30 days.
11. Subjects who have a history of neuroleptic malignant syndrome.