Sleep disorders are serious issues in modern society. There has been marked scientific interest in sleep for a century, with the discoveries of the electrical activity of the brain (EEG), sleep-wake system, rapid eye movement (REM) sleep, and circadian rhythm system. Additionally, the advent of video-polysomnography in clinical research has revealed some of the consequences of disrupted sleep and
sleep deprivation in
psychiatric disorders. Decades of clinical research have demonstrated that
sleep disorders are intimately tied to not only physical disease (e. g., lifestyle-related disease) but
psychiatric illness. According to The International Classification of
Sleep Disorders (2005),
sleep disorders are classified into 8 major categories: 1)
insomnia, 2) sleep-related breathing disorders, 3)
hypersomnias of central origin, 4)
circadian rhythm sleep disorders, 5)
parasomnias, 6) sleep-related
movement disorders, 7) isolated symptoms, and 8) other
sleep disorders. Several
sleep disorders, including
obstructive sleep apnea syndrome,
restless legs syndrome,
periodic limb movement disorder,
sleepwalking,
REM sleep behavior disorder, and
narcolepsy, may be comorbid or possibly mimic numerous
psychiatric disorders, and can even occur due to psychiatric
pharmacotherapy. Moreover,
sleep disorders may exacerbate underlying
psychiatric disorders when left untreated. Therefore, psychiatrists should pay attention to the intimate relationship between
sleep disorders and psychiatric symptoms. Sleep psychiatry is an academic field focusing on interrelations between sleep medicine and psychiatry. This mini-review summarizes recent findings in sleep psychiatry. Future research on the bidirectional relation between sleep disturbance and psychiatric symptoms will shed light on the pathophysiological view of
psychiatric disorders and
sleep disorders.