Healthy Bodies, Healthy Kids

INCLUSION CRITERIA * 6-18 years old (at any point during study participation) * BMI percentile \> 85 * Meet DSM-IV criteria for one or more childhood onset psychiatric disorders including disruptive behavior disorders (attention deficit disorder, conduct disorder, oppositional defiant disorder and disruptive behavior disorder not otherwise specified), affective disorders (bipolar affective disorder, major depressive disorder and mood disorder not otherwise specified), anxiety disorders (generalized anxiety disorder, obsessive compulsive disorder, separation anxiety, social and other specific phobias) as well as other disorders, including autism spectrum disorders (autistic disorder, Asperger's Syndrome and pervasive developmental disorder not otherwise specified), psychotic disorders (schizophreniform disorder, schizophrenia and psychotic disorder not otherwise specified) and movement disorders (tic disorder, Tourette's Syndrome) as determined by semi-structured diagnostic interview (EXCEPT for the Obese or Overweight Control Group, none of whom can meet criteria for any DSM-IV Axis I psychiatric illness) * Currently treated with an atypical antipsychotic medication (EXCEPT for the Obese or Overweight Healthy Control Group, none of whom can be treated with any psychotropic medications Participants treated with any psychotropic medication may not have any medication changes for 1 month prior to study enrollment at the discretion of the PI, and Antipsychotic-Treated Participants must be treated with an antipsychotic \> approximately 12 weeks with no antipsychotic medication dose changes for 1 month * The Healthy Overweight or Obese Control Group may not be currently taking any prescription medications (multivitamins, over the counter medications, glucocorticoid nasal spray and inhalers are permitted, as well as non-sedating antihistamines such as but not limited to Claritin (loratadine) and Zyrtec (cetirizine) * Participants between 6-17 years old will be able to give assent and have a parent/guardian that can provide written informed consent, and 18 year-old participants will be able to provide written informed consent. EXCLUSION CRITERIA * Do not meet DSM-IV criteria for any Axis I psychiatric illness per PI discretion (EXCEPT for Overweight or Obese Healthy reference group) * Any lifetime use of antipsychotics (EXCEPT for Antipsychotic-Treated Participants, with the individuals in the latter group possibly having a remote, brief prior antipsychotic exposure that may be considered for enrollment on a case by case basis by the PI) * The presence of any serious medical disorder that may confound the assessment of relevant biologic measures or diagnoses, including: significant organ system dysfunction; endocrine disease, including type 1 or type 2 diabetes mellitus; coagulopathy; anemia; or acute infection; all based on PI discretion Participants regularly taking within the last 3 months any glucose lowering agent, lipid lowering agent, exogenous testosterone, recombinant human growth hormone, or any other endocrine agent that might confound substrate metabolism, oral glucocorticoids (glucocorticoid nasal spray and inhalers are permitted), sedating antihistamines (non-sedating antihistamines such as but not limited to Claritin (loratadine) and Zyrtec (cetirizine) are permitted), and certain mood stabilizing agents including antiepileptic medications (lamotrigine is permitted) and Lithium, as these medications may themselves worsen or otherwise alter weight gain, glucose and lipid regulation or otherwise make it difficult to assess the effects of the antipsychotic alone; (note that exposure to many psychotropic agents including stimulants, SSRI's and SNRI's are permitted in the Antipsychotic-Treated and Non-Antipsychotic Treated Groups in Study 1 in order to maintain the generalizability of the sample) * IQ \< 70 (based on school records and/or evaluation by clinician and at the discretion of the PI) * Current DSM IV diagnosed substance abuse or dependence * Past history of, or current dyskinesia * Stimulant dosage significantly higher (per PI judgment) than the equivalent of approximately 2 mg/kg/day methylphenidate equivalent dose (EXCEPT in the Obese or Overweight Control Group, none of whom can be taking stimulant medications) * Unable to provide assent or informed consent * Active suicidality or a primary diagnosis of depression * Unwilling to allow study staff to contact subject's primary care physician to alert to any significant, abnormal clinical findings or test results obtained as part of study participation