Disturbances in circadian rhythm-related physiological and behavioral processes are frequently observed in depressed patients and several clock genes have been identified as risk factors for the development of mood disorders.
The fact that chronotherapies, including SDT and sleep phase advance, are dramatically effective suggests that altered clock gene machinery may represent a core pathophysiological defect in a subset of mood disorder patients.
Fortunately, recent publications have addressed this problem and there is now some evidence available highlighting the relevance of CLOCK genes in conditions, such as ADHD, mood disorders, schizophrenia and anxiety disorders.