Patients 18 years of age and older with Cushing's syndrome not related to ACTH production may participate in this study. Candidates will be have a history and physical examination, electrocardiogram, urine, blood and saliva tests, and a computerized tomography (CT) scan of one or both adrenal glands. They will fill out questionnaires on their disease symptoms, quality of life, and on basic information about themselves, such as marital status, education level, place of residence, etc. Finally, they will have a corticotropin-releasing hormone (CRH) test to confirm that they have the form of Cushing's syndrome under study in this protocol. This test involves collecting blood samples at intervals before and after administration of sheep CRH to measure cortisol and ACTH levels.