Hypersomnia

An extreme daytime sleepiness and a persistent, overwhelming urge to sleep, even after getting a full night's rest. Possible causes are sleep disorders (sleep apnea, narcolepsy, insufficient sleep syndrome), neurological condition (brain injury, multiple sclerosis, Parkinson's disease, Kleine-Levin syndrome, epilepsy, brain tumor), thyroid disease, medications (sedatives, narcotics, cannabis, alcohol), and psychiatric disorders (depression, bipolar disorder).