Inclusion Criteria:

1. Male and female outpatients 6-17 years of age (inclusive).

2. Subjects with the diagnosis of Bipolar or Bipolar Spectrum Disorder and currently displaying manic, hypomanic, or mixed symptoms (with or without

   psychotic features), by DSM-IV, as manifested in clinical evaluation and confirmed by structured interview. Bipolar Spectrum Disorder (or sub- threshold bipolar disorder) is operationalized as having severe mood disturbance, which meets DSM-IV Criteria A for bipolar disorder but display fewer elements in Criteria B (only require 2 items for elation category and 3 for irritability).

3. Subjects must score ≥ 20 on the YMRS.

4. Subjects and their legal representative must have a level of understanding sufficient to communicate intelligently with the investigator and study coordinator, and to cooperate with all tests and examinations required by the

   protocol.

5. Subjects and their legal representative must be considered reliable reporters.
6. Each subject and his/her authorized legal representative must understand the nature of the study. The subject's authorized legal representative must sign an informed consent document and the subject must sign an informed assent document (if ≥ 7 years old).
7. Subject must be able to participate in mandatory blood draws.
8. Subject must be able to swallow pills.
9. Subjects with comorbid ODD, CD, OCD, PDD, anxiety and depressive disorders will be allowed to participate in the study provided they do not meet for any of the exclusionary criteria.
10. For concomitant therapy used to treat ADHD, subjects must have been on a stable dose of the medication for 1 month prior to study enrollment. The dose of the ADHD therapy will not change throughout the duration of the study.

Exclusion Criteria:

1. Investigator and his/her immediate family; defined as the investigator's spouse, parent, child, grandparent, or grandchild.
2. Serious, unstable illness including hepatic, renal, gastroenterological, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, or hematologic disease.
3. Uncorrected hypothyroidism or hyperthyroidism.
4. Non-febrile seizures without a clear and resolved etiology.
5. DSM-IV substance (except nicotine or caffeine) dependence within past 6 months.
6. Judged clinically to be at serious suicidal risk.
7. Any other concomitant medication with primary central nervous system activity other than specified in the Concomitant Medication portion of the protocol.
8. Current diagnosis of schizophrenia.
9. Mental retardation (IQ < 75).
10. Pregnant or nursing females.
11. Known hypersensitivity to Invega® or similar formulations (paliperidone, risperidone).
12. A non-responder or history of intolerance to Invega®, after treatment at adequate doses as determined by the clinician.
13. Severe allergies or multiple adverse drug reactions.
14. Subjects with a hematological disorder.
15. Subjects with diabetes.