This will be a 12-week open-label pilot treatment study for children and adolescents (ages 6-17) who meet DSM-IV criteria for bipolar disorder (BPD) and obsessive-compulsive disorder (OCD) who are adequately mood stabilized on a stable regimen based on standard clinical care. Specific hypotheses are as follows:

Hypothesis 1: Children and adolescents with comorbid OCD and BPD who have achieved adequate mood stabilization using a naturalistic clinical practice approach, will benefit from an FDA-approved SSRI on their OCD symptoms in a clinically meaningful way without exacerbation of bipolar symptoms.

As no systemic data is available regarding the efficacy and safety of SSRI in the treatment of OCD+BPD children, it calls for a preliminary open pilot treatment study to explore these issues as a logical first step that could lead to systematic randomized controlled trials in the future. SSRI's are the first line and most commonly used anti-OCD agents. It remains unknown, which of the standard SSRIs is least activating for youth with BPD. Fluoxetine along with fluvoxamine and sertraline are FDA approved for the treatment of OCD in children. Fluoxetine remains the most extensively studied SSRI in children. We will test the safety and efficacy of fluoxetine in children and adolescents with BPD and OCD.

The proposed study includes 1.) the use of a 12-week design to document the response rate and 2.) careful assessment of safety and tolerability

• Pediatric Bipolar Disorder
• Pediatric OCD

Inclusion Criteria:

• Male or female participants between 6 and 17 years of age.
• Participants must have DSM-IV diagnosis of OCD and bipolar (I or II) disorder, displaying current OCD symptoms of at least moderate impairment (CY-BOCS ≥ 15) and for at least 4 weeks prior to participation maintained on steady dose of mood stabilizing medication (lithium, anticonvulsants or atypical antipsychotics) with minimal or mild mood symptoms (YMRS ≤ 15). Period of mood stabilization will be determined by clinician judgment and confirmed by K-SADS-E.
• Subject and his/her 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.
• Subjects and his/her legal representative must be considered reliable.
• Each subject and his/her authorized legal representative must understand the nature of the study. The subject's authorized legal representative and the subject must sign an IRB approved informed consent and assent document respectively.
• Subject must be able to participate in mandatory blood draws.
• Subject must be able to swallow pills.
• Subjects with comorbid ADHD, ODD, CD, or other anxiety disorders will be allowed to participate in the study provided they do not meet any exclusionary criteria.

Exclusion Criteria:

• DSM-IV substance dependence (except nicotine or caffeine) within past 3 months.
• History of anti-depressant induced mania or hypomania while also being treated with appropriate dosage(s) of mood stabilizers.
• Pregnant or nursing females.
• Investigator and his/her immediate family, defined as the investigator's spouse, parent, child, grandparent, or grandchild.
• Serious, unstable systemic illness.
• History of severe allergies or multiple adverse drug reactions.
• Non-febrile seizures without a clear and resolved etiology.
• Clinically judged to be at serious suicidal risk.
• Other concomitant medication with primary central nervous system activity other than those specified in the Concomitant Medication protocol.
• History of allergic reaction to SSRIs.
• Participants using an MAOI within two weeks prior to receiving study medication.
• Current diagnosis of schizophrenia.
• Uncorrected hypo or hyperthyroidism.
• Active symptoms of anorexia or bulimia nervosa
• Non-response of OCD symptoms to fluoxetine as defined by being on therapeutic dose of fluoxetine for at least 10 weeks.
• Current treatment with antidepressant medication.