Patient description: A 26-year-old obese woman with a history of bipolar disorder complains that her recent struggles with her weight and eating have caused her to feel depressed. She states that she has recently had difficulty sleeping and feels excessively anxious and agitated. She also states that she has had thoughts of suicide. She often finds herself fidgety and unable to sit still for extended periods of time. Her family tells her that she is increasingly irritable. Her current medications include lithium carbonate and zolpidem.

Clinical trial eligibility criteria: eligible ages (years): 7.0-17.0,  Bipolar Disorder Participants aged 7 years to 17 years, 11 months old at time of first dose Participants must meet DSM-IV diagnostic as assessed by a semi-structured assessment (KSADS-PL) and a separate clinical interview with a child/adolescent psychiatrist for manic or mixed episodes in bipolar I disorder Score of > 20 on the YMRS at screening and baseline The participant and legal guardian must understand the nature of the study and be able to comply with protocol requirements. The legal guardian must give written informed consent and the youth, written assent Participants with comorbid conditions [attention deficit hyperactivity disorder (ADHD), conduct disorder], except those listed in Criterion 2, may participate If female: is premenarchal, or is incapable of pregnancy because of a hysterectomy, tubal ligation, or spousal/partner sterility. If sexually active and capable of pregnancy, has been using an acceptable method of contraception (hormonal contraceptives, intrauterine device, spermicide and barrier) for at least one month prior to study entry and agrees to continue to use one of these for the duration of the study. If sexually abstinent and capable of pregnancy, agrees to continued abstinence or to use of an acceptable method of birth control should sexual activity commence Has a negative quantitative serum ß-human chorionic gonadotrophin hormone pregnancy test at screening and a negative qualitative urine pregnancy test at baseline, if female Participants with a history of substance abuse may participate if they agree to continue to abstain from drugs during the trial and have a negative drug screen at screening or prior to baseline. Those with an initial positive drug screen during screening may have another screen done 1-3 weeks later while in screening, and a negative result will allow the participant to participate The participant is willing and clinically able to wash out of medications during the screening period. Prior to the administration of lithium, participants will have not used any of the following medications: antipsychotics, monoamine oxidase inhibitors, antidepressants within the preceding 2 weeks; stimulants within the preceding week; or fluoxetine or depot antipsychotics in the past month (no stable participants will be asked to discontinue medications) ECG and bloodwork including CBC, electrolytes, etc. (as per Safety assessment procedures listed in Table 6) showing no clinically significant abnormalities  Participant who is clinically stable on current medication regimen for bipolar disorder A current or lifetime diagnosis of Schizophrenia or Schizoaffective Disorder, a Pervasive Developmental Disorder (ASQ score > 15), Anorexia Nervosa, Bulimia Nervosa, or Obsessive-Compulsive Disorder Current DSM-IV diagnosis of Substance Dependence Positive drug screen at screening and on retest 1-3 weeks later Participants with symptoms of mania that may be attributable to a general medical condition, or secondary to use of medications (e.g., corticosteroids) Evidence of any serious, unstable neurological illness for which treatment under the auspices of this study would be contraindicated Any serious, unstable medical illness or clinically significant abnormal laboratory assessments that would adversely impact the scientific interpretability or unduly increase the risks of the protocol Current general medical condition including neurological disease, diabetes mellitus, thyroid dysfunction, or renal dysfunction that might be affected adversely by lithium, could influence the efficacy or safety of lithium, or would complicate interpretation of study results Evidence of current serious homicidal/suicidal ideation such that in the treating physician's opinion it would not be appropriately safe for the participant to participate in this study Evidence of current active hallucinations and delusions such that in the treating physician's opinion it would not be appropriately safe for the participant to participate in this study