A dyssomnia consisting of prolonged or daytime sleep episodes occurring almost daily. The hypersomnia is called primary if it is not related to another mental disorder, substance induced, or due to a general medical condition.
Excessive amount of sleep, sometimes with confusion on waking.
Sleep lasting for exceptionally long periods, as occurs in some cases of brain inflammation.
Excessive daytime sleepiness resulting from any cause (e.g., inadequate sleep hygiene, the use of intoxicating drugs, or obstructive sleep apnea).