A dyssomnia is a disorder of getting to sleep or staying asleep or of excessive sleepiness. The person typically experiences changes in the amount and/or timing of sleep, and how restful it is. The dyssomnias are disorders of sleep or wakefulness, in contrast to parasomnias, which are about the sleep/wake transition.

Dyssomnias include extrinsic (caused by factors outside the body), intrinsic (caused by factors inside the body), and circadian-rhythm sleep disorders. When people say they have sleeping problems, they usually are referring to one or more dyssomnia.





Restless legs syndrome

Periodic limb movement disorder


Toxin-Induced Sleep Disorder

Kleine-Levin syndrome


Altitude insomnia

Insomnia due to substance use/abuse

Sleep-onset association disorder

Nocturnal paroxysmal dystonia

Limit-setting sleep disorder

Circadian-rhythm sleep disorders

Delayed Sleep Phase Syndrome

Advanced Sleep-Phase Syndrome

Jet lag - Time Zone Shfit Syndrome

Free-running disorder

Shift Work Sleep Disorder

Irregular Sleep Wake Rhythm Disorder

Familial Advanced Sleep-Phase Syndrome


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