There is a scarcity of clinical trials assessing the effects of medications in children with bipolar disorder. This study aims to assess the efficacy of Aripiprazole associated with Methylphenidate (MPH)for the treatment of children and adolescents with bipolar disorder comorbid with ADHD who improve in maniac symptoms while receiving aripiprazole but did not have an adequate response in ADHD symptoms. The study design is a 4-week randomized, double blind, cross-over group trial. Patients were randomized to aripiprazole + MPH or aripiprazole + placebo. The main hypothesis is: Aripiprazole + MPH will significantly reduce ADHD scores compared to aripiprazole + placebo.

Bipolar disorder (BD) is a chronic disorder that severely affects the normal development of children and adolescents. The disorder is associated with high rates of suicide and high-risk behaviors like sexual promiscuity and drug abuse. Bipolar disorder in children is also associated with high rates of comorbidity, especially with Attention-Deficit Hyperactivity Disorder (ADHD). There is a scarcity of clinical trials assessing the effects of medications in children with BD. Moreover, the frequent presence of comorbid ADHD might determine lower response to treatment. Aripiprazole is a novel anti-psychotic drug. Its mechanism of action seems to be related to a stabilization of dopaminergic transmission, acting as a partial agonist especially in dopaminergic D2 receptors. It also has effects in 5-HT1a serotonergic receptors. Thus, it might have a promising effect in children and adolescents with comorbid BD and ADHD. A retrospective chart review, recently published, suggests the efficacy of this drug in children with BD. This study aims to assess the efficacy of Aripiprazole associated with Methylphenidate (MPH) for the treatment of 20 children and adolescents (age range: 8 to 17 years-old) with Bipolar Disorder comorbid with ADHD who improve in maniac symptoms while receiving aripiprazole but did not have an adequate response in ADHD symptoms. The study design is a 4-week randomized, double blind, cross-over group trial. Patients were randomized to aripiprazole + MPH or aripiprazole + placebo. The hypotheses are: 1) Aripiprazole + MPH will significantly reduce ADHD scores compared to aripiprazole + placebo. 2) Patients receiving aripiprazole + MPH will not deteriorate in maniac symptoms.

Inclusion Criteria:

• Age: 8 -17
• BD type I or II comorbid with ADHD
• Reduction of maniac symptoms (30% reduction in the YMRS scores and/or CGI scores ≤ 2)while using aripiprazole during a previous study (NCT00116259)without improvement of ADHD symptoms (reduction in ADHD symptoms < 30% in the SNAP-IV). Those receiving placebo in the previous protocol will receive a 6- week open label treatment with aripiprazole. The same threshold for reducing maniac symptoms and absence of response in ADHD symptoms will be used.

Exclusion Criteria:

• IQ < 70
• Pregnancy or absence of a contraceptive method in fertile girls
• Diagnoses: pervasive development disorder, schizophrenia, drug abuse or dependency
• Risk of suicide or homicide
• Clinical condition that might interfere in the study
• Known sensibility to aripiprazole