Effect of Rimonabant on Weight Gain and Body Composition in Adults With Prader Willi Syndrome

Inclusion Criteria: 1. Subjects will be selected if they have Prader Willi Syndrome previously confirmed by standard genetic testing (the DNA methylation test) or meet the clinical diagnostic criteria as follows :the presence of at least four of the six principal characteristics of PWS syndrome including 1) infantile hypotonia, 2) abnormal pubertal development, 3) obesity after early infancy, 4) dysfunctional central nervous system performance, 5) dysmorphic facial features, and 6) short stature. In addition, they must have one or more of the following characteristics commonly associated with PWS: 1) small hands and feet, 2) skin problems, 3) behavioral problems related to food, and 4) decreased pain sensitivity. 2. Subjects must be 18 to 35 years of age and fairly cooperative with the study protocol. 3. Subjects must have a BMI of at least 30 or more. Exclusion Criteria: 1. Presence of pulmonary disease. 2. Presence of any other abnormal endocrine findings, including abnormal thyroid function. 3. Presence of significant behavioral problems or psychiatric illness including anxiety disorder and depression, interfering with the follow up of protocol. Any degree of depression and moderate to severe anxiety will be exclusion criteria for this study. 4. Subjects with Prader Willi Syndrome who are on other medications including growth hormone therapy, anti epileptic medications, or antipsychotic medications. 5. The presence of moderate to severe renal or liver disease. Mild elevations of liver enzymes are not exclusive. 6. Subjects who are on any other research or weight loss medication