Sleep disorders: a selective update.

Recent years have seen significant advances in sleep disorders medicine, including effective treatments for chronic psychophysiological insomnia and obstructive sleep apnea syndrome; greater understanding of biological rhythms and of the nature of sleep in depression, including seasonal affective disorder; and the discovery of REM behavior disorder. The author reviews selected developments in the sleep disorders field over the last three years. Developments are presented in the framework of the diagnostic classification of the American Sleep Disorders Association, with emphasis on areas relevant to the practice of psychiatry.