Chronobiological disorders: current and prevalent conditions.

In recent decades, the hectic lifestyle of industrialized societies has wrought its effects on the quality of sleep, and these effects are evidenced by a profusion of sleep-related disorders. Regular exposure to artificial light, coupled with social and economic pressures have shortened the time spent asleep. Otherwise, Circadian Rhythm Sleep Disorders are characterized by desynchronization between the intrinsic circadian clock and the extrinsic cycles of light/dark and social activities. This desynchronization produces excessive sleepiness and insomnia. The International Classification of Sleep Disorders describes nine sleep disorders under the category of Circadian Rhythm Sleep Disorders. Currently, this diagnosis is made based on the patient's history, a sleep log alone, or the sleep logs and actigraphy conducted for at least 7 days. This review contains an overview of current treatment options, including chronotherapy, timed bright light exposure, and administration of exogenous melatonin.