Inclusion Criteria:

1. Age 18 to 65 years
2. Body mass index (BMI) >=25;
3. Currently taking a regimen of medications for bipolar disorder likely to cause, sedation, weight gain or undesirable metabolic effects;
4. Able to give basic informed consent
5. Meets DSM-IV criteria for lifetime bipolar I or II disorder and are presently in sustained remission (CGI BP<3 in the previous 8-week period measured through a complete psychiatric history at screening and patient report.)
6. Epworth Scale Score > 7
7. Women of childbearing potential must agree to use a doctor-approved birth control throughout participation in the study

Exclusion Criteria:

1. Unwilling or unable to comply with study requirements (i.e., complete forms, attend scheduled evaluations)
2. Not competent to provide informed consent in the opinion of the investigator
3. Ultra-rapid cycling (>4 episodes per month) bipolar I disorder
4. Unstable and severe medical illness that requires immediate and intensive medical attention, When appropriate, the patients can be reconsidered for inclusion in the study if/when their medical condition becomes compatible with participation in a protocol-driven research study
5. Women who are planning to become pregnant, currently pregnant, or breast-feeding;
6. Current substance dependence; however, if a subject only has substance abuse/use, after the first positive drug screen, another drug screen will be repeated. If that drug screen is positive, the subject will be excluded. If the second drug screen is negative, the subject will be considered for the study;
7. Subjects who have previously failed an adequate trial of aripiprazole.
8. Subjects with a suicide attempt in the past 2 years;
9. Subjects with a history of inpatient admission in the past 1 year;
10. Subjects with a history of homicidal ideation;
11. Any subject for whom the PI deems that the potential risks in participating in the study outweigh the potential benefits.