Brain Imaging Study of Adults With Autism Spectrum Disorders

* INCLUSION CRITERIA: Healthy Controls: Age between 18 years and 40 years. Blood Pressure (BP) less than 140/90 Normal EKG. Menstrual phase: Female participants will be tested only during the follicular phase of their menstrual cycle (defined as days 6-12 after the first day of the last menstrual period). Patients: A diagnosis of autism, Asperger s disorder, or PPD NOS. IQ \> 80. Age between 18 years and 40 years. Blood Pressure (BP) less than 140/90 Normal EKG. Menstrual phase: Female participants will be tested only during the follicular phase of their menstrual cycle (defined as days 6-12 after the first day of the last menstrual period). EXCLUSION CRITERIA: Healthy Controls: Impaired hearing. Head trauma with loss of consciousness in the last year or any evidence of functional impairment due to and persisting after head trauma. Having a known risk from exposure to high magnetic fields (e.g. participants with pace makers) or having metallic implants (e.g. braces) in the head region (likely to create artifact on the MRI scans). Past or present psychiatric, neurological, or severe chronic medical illness. This includes the absence of substance abuse histories, learning disabilities and all DSM IV disorders. The investigators will evaluate medical histories. Potential subjects with medical conditions that are judged not to interfere with the study may be allowed to participate. Use of medications or drugs that would interfere with study results. This includes contraceptive hormones, steroids, medications for psychiatric symptoms like anxiety or depression, stimulants, and medications for high blood pressure. Participants will be asked to tell the investigators of any medications or drugs that they are taking. The investigators will consider the drug interactions with oxytocin and vasopressin prior to study, and participants will not be able to participate in the study if the drug interactions could be dangerous. Pregnancy or Nursing Status: Because of the risk to an unborn fetus or infant, women who are pregnant or nursing are excluded from this protocol. Therefore, all women of childbearing potential will have a pregnancy test performed no more than 24 hours before each drug administration and will not be able to participate if the pregnancy test is positive. Patients: Impaired hearing. Head trauma with loss of consciousness in the last year or any evidence of functional impairment due to and persisting after head trauma. Having a known risk from exposure to high magnetic fields (e.g. participants with pace makers) or having metallic implants (e.g. braces) in the head region (likely to create artifact on the MRI scans). A known neurological or neurogenetic condition, such as uncontrolled epilepsy, cerebral palsy, and chromosomal abnormalities. Use of medications or drugs that would interfere with the study results (see above). Pregnancy or Nursing Status: Because of the risk to an unborn fetus or infant, women who are pregnant or nursing are excluded from this protocol. Therefore, all women of childbearing potential will have a pregnancy test performed no more than 24 hours before each drug administration and will not be able to participate if the pregnancy test is positive.