Hypersomnia: Hypersomnia is a condition characterized by episodes of prolonged nighttime sleep or excessive daytime sleepiness. Symptoms include anxiety, increased irritation, decreased energy, slow thinking, slow speech, loss of appetite, and more. Causes of hypersomnia include other sleep disorders, physical problems such as tumor or head trauma, medications, medical conditions such as multiple sclerosis, depression, epilepsy, obesity, and encephalitis, and genetic predisposition. Treatment for hypersomnia is generally with medication and changes in behavior.