hypersomnia

Hypersomnia is a sleep disorder defined by persistent, excessive daytime sleepiness that interferes with daily activities, often accompanied by prolonged nighttime sleep or extended naps. It is distinct from temporary fatigue and from voluntary oversleeping. Hypersomnia can be a primary condition or secondary to another problem.

Core symptoms are excessive daytime sleepiness and prolonged nocturnal sleep. People may experience sleep attacks, prolonged naps that do not fully relieve sleepiness, and mental clouding on waking (sleep inertia).

Causes can be primary (idiopathic hypersomnia, Kleine-Levin syndrome) or secondary to other sleep disorders (sleep apnea, circadian rhythm disorders), medical or psychiatric conditions, or medications and substances.

Diagnosis relies on patient history, sleep logs, and sleep studies. Overnight polysomnography followed by the multiple sleep latency test helps distinguish hypersomnia from other causes of tiredness and can aid in identifying narcolepsy (short sleep latencies with sleep-onset REM periods).

Management focuses on treating underlying causes, improving sleep quality, and promoting daytime alertness. Approaches include sleep hygiene, scheduled daytime naps, and wake-promoting medications such as modafinil or pitolisant; sodium oxybate is used in some forms of narcolepsy. Cognitive behavioral strategies and treatment of comorbid conditions may help. Prognosis varies; some individuals respond to treatment, while others have persistent symptoms.