<unk>  (IH) is a neurological disorder which is characterized primarily by excessive sleep and excessive daytime sleepiness (EDS). The condition typically becomes evident in early adulthood and most patients diagnosed with IH will have had the disorder for many years prior to their diagnosis. , an FDA-approved medication exists for IH, in addition to several off-label treatments (primarily FDA-approved narcolepsy medications).<unk>  may also be referred to as IH, IHS, or primary<unk>  and belongs to a group of sleeping disorders known as central<unk> s, central disorders of hypersomnolence, or<unk>  of brain origin. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) defines<unk>  as EDS without narcolepsy or the associated features of other sleep disorders. It occurs in the absence of medical problems or sleep disruptions, such as sleep apnea, that can cause secondary<unk> .
Idiopathic hypersomnia
Strephosymbolia
Psychoorganic syndrome
Nightmare disorder
Erotolepsy
Interictal dysphoric disorder
Narcolepsy
Klazomania