OBSOLETE: Idiopathic hypersomnia with long sleep time

Idiopathic hypersomnia with long sleep time is an obsolete diagnostic category that was previously used to describe a subtype of idiopathic hypersomnia characterized by excessive daytime sleepiness accompanied by prolonged nocturnal sleep episodes, typically exceeding 10 hours. Patients experienced great difficulty waking up (known as sleep inertia or sleep drunkenness), with confusion and irritability upon awakening. Despite obtaining long periods of sleep, individuals did not feel refreshed. The condition primarily affects the central nervous system, specifically the brain's sleep-wake regulation mechanisms. This classification has been retired and merged into the broader diagnosis of idiopathic hypersomnia, as the International Classification of Sleep Disorders (ICSD-3) no longer distinguishes between subtypes with and without long sleep time. The key clinical features include excessive daytime sleepiness, prolonged and unrefreshing nighttime sleep, severe sleep inertia, and long unrefreshing daytime naps. Unlike narcolepsy, patients do not experience cataplexy or abnormal REM sleep intrusions. The exact cause remains unknown, and no specific genetic or biological marker has been identified. Treatment options for idiopathic hypersomnia are limited and primarily symptomatic. Wake-promoting agents such as modafinil and, in some cases, stimulants like methylphenidate or amphetamine derivatives may be used to manage excessive daytime sleepiness. More recently, lower-sodium oxybate (marketed as Xywav) has been approved for the treatment of idiopathic hypersomnia in adults. Behavioral strategies including scheduled naps and sleep hygiene optimization may provide some benefit, though naps are typically unrefreshing in this condition.

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