Treatment of Overweight Induced by Antipsychotic Medication in Young People With Autism Spectrum Disorders (ASD)

Inclusion Criteria:

1. Diagnosis of Autism Spectrum Disorder (autistic disorder, pervasive developmentaldisorder not otherwise specified), Asperger's disorder) based upon an AutismDiagnostic Observation Scale (ADOS) and Diagnostic and Statistical Manual (DSM-IV)interview.

2. Minimum of 1 month on a stable atypical antipsychotic dose with no plans to change thedose for the next 4 months.

3. A documented greater than/equal to 7% increase in BMI since starting atypicalantipsychotic therapy(going back as far as prior 12 months); or, if BMI is greater orequal to 85th percentile corrected for age and sex, then a greater than 5% body weightincrease per year (prorated at greater than 5% body weight increase if medicated forlonger than a year).

4. Age 6 years to 17 years, 4 months.

5. Subjects and their parents (guardians) must be judged reliable for medicationcompliance and must agree to keep appointments for study visits and tests as outlinedin the protocol.

6. Prior to the conduct of any study-specific procedures, the subject must provide assentto participate in the study (if developmentally appropriate), and their parents (guardians) must provide written informed consent.

Exclusion Criteria:

1. History of intolerable adverse effects with metformin.

2. Prior history of an exposure to metformin of sufficient dose or duration to determineresponse status.

3. History of liver disease, renal impairment, congestive heart failure, perniciousanemia, any other condition increasing the risk for lactic acidosis, or any seriousmedical illness requiring treatment.

4. Use of cationic drugs excreted by the kidneys.

5. Planned surgery or procedure requiring contrast.

6. Pregnant at screening contact.

7. On other psychotropic concomitant medications for less than 2 months.

8. Treatment or planned treatment with concomitant medications with unacceptableinteractions with metformin, including topiramate, levetiracetam, beta blockers,angiotensin-converting-enzyme (ACE) inhibitors, diuretics, or histamine H2 receptorantagonists.

9. Unable to tolerate blood work.

10. Current use of medication for target symptoms of appetite or weight loss.

11. Planned change of medication, medication dose, or behavioral treatment targetingweight loss during the study period.