Improving Metabolic Parameters of Antipsychotic Child Treatment With Ziprasidone, Aripiprazole, and Clozapine

Inclusion Criteria: * Ages 10 to 17 years (inclusive). * Receiving treatment with ziprasidone, aripiprazole or clozapine for the past 56 days or longer. * Clinically stable on current treatment regimen (see Rationales below). * Stable dose of current psychotropic co-medications for at least 30 days. * BMI increase of \> 7% within 3 months OR a \> 0.5 BMI z-score increase within the past 24 months while taking olanzapine, quetiapine or risperidone, with maintenance of the threshold level of weight gain. * Lifetime diagnosis of a schizophrenia spectrum disorder (schizophrenia, schizoaffective disorder, psychotic disorder NOS), a bipolar spectrum disorder (bipolar disorder, bipolar disorder NOS), certain mood disorders (mood disorder NOS, major depressive disorder with psychotic features), or certain disruptive/aggressive disorders (conduct disorder, intermittent explosive disorder, autism spectrum disorder with history of clinically significant levels of disruptive behaviors as defined below) using DSM-IV criteria determined by clinical interview and K-SADS-PL. * Sexually active girls must agree to use an effective form of birth control or be abstinent. * Principle caretaker is able to participate in study appointments as is clinically indicated. * guardian and the child must agree (legally consent and assent) to participation. Exclusion Criteria: * Any medication that would significantly alter glucose, insulin or lipid levels. Prohibited medications will include, but are not limited to: insulin, steroids, topiramate, sibutramine, orlistat, metformin, amantadine, vitamin E (other than in standard multivitamins), antidiabetic drugs, HIV drugs. * Major neurological disorder or medical illness that affects weight gain (e.g., unstable thyroid disease), requires a prohibited systemic medication or procedure (e.g., diabetes mellitus \[insulin\], chronic renal failure \[steroids\]) or that would prevent participation in physical activity in the healthy lifestyle program. * Current active thyroid (TSH \>18 microIU/ml), hepatic (2 LFTs \>4x upper limits of normal), renal (serum Creatinine \>1.4 mg/dL in females and serum Creatinine \>1.5 mg/dL in males), cardiac, gastrointestinal, or adrenal disease. * Fasting glucose \> 125 mg/dL on two occasions indicating need for prompt treatment for diabetes. * Child meets DSM-IV criteria for substance abuse or dependence disorder within the past month, not including tobacco abuse or dependence • Current treatment with more than one antipsychotic medication. * Current treatment with more than 5 total psychotropic medications (i.e., 4 psychotropics plus SGA). * Known hypersensitivity to metformin. * Pregnant or breast feeding. * Current or lifetime diagnosis of anorexia nervosa or bulimia nervosa. * Significant risk for dangerousness to self or to others that makes participating inadvisable. * Language issues that prevent child and/or parent from completing assessments or treatment. * Ongoing or previously undisclosed child abuse requiring new department of social service intervention.