The purpose of this study is to prospectively study patients with Cushing's syndrome before and after treatment, with a special emphasis on physical function, quality of life, and circadian rhythms. The hypotheses are: * Cushing's syndrome negatively impacts health-related quality of life (HRQoL) and physical functioning * Cushing's syndrome is associated with altered circadian rhythms at the whole body level and in peripheral target tissues. * These complications partially reverse following disease control.