Commonly hypersomnia can be caused by either a primary disorder causing increased sleepiness like narcoplepsy/idiopathic hypersomnia or secondary to sleep deprivation, drugs, disturbed sleep at night, sleep apnea. The person tends initially to fall asleep while doing monotonous activities like riding a vehicle, sitting idle, or reading a book. However gradually it impacts important activities because of an uncontrolled urge to sleep. Other symptoms may include anxiety, increased irritation, decreased energy, restlessness, slow thinking, slowed speech, loss of appetite, hallucinations, and memory difficulty. Primary Hypersomnia typically affects adolescents and young adults with an average age of 15 years. Primary hypersomnia is caused by a disturbance of a hormone called hypocretin. An adult is considered to have primary hypersomnia if he or she sleep more than 12 hours in night with frequent day time naps that are not refreshing and has sleep drunkenness. Idiopathic hypersomnia also has an association with depression. Other causes include dysfunction of the autonomic nervous system, or drug or alcohol abuse.

However rather than primary hypersomnia which are rare, the commonest cause of day time excessive sleepiness is obstructive sleep apnea . Obstructive sleep apnea is characterized by obstruction to breathing while sleeping leading to loud snoring and incomplete oxygenation to brain leading to microarousals causing disturbed sleep at night

After analysis of the symptoms overnight polysomnography with or without multiple sleep latency test are conducted in a sleep laboratory. This important as once the disease is characterized, therapeutic interventions can markedly improve the quality of life. The people who have increased sleepiness due to idiopathic hypersomnia and narcolepsy can use stimulants like methyphenidate, modafinil and sidium oxybate. Obstructive sleep apnea and snoring may improve by exercise and weight loss or it can be improved by continuous positive airway pressure ( CPAP) machine. If properly used this machine remove the obstruction to breathing and restore a good night sleep thus preventing daytime somnolence. To conclude oversleeping is a problem that may lead to subtle physical and behavioral manifestations which we neither understand nor relate to this disorder. However a systematic search for a cause and appropriate treatment can improve the quality of life significantly.