Hypersomnolence disorder, also known as excessive daytime sleepiness, is a sleep disorder characterized by excessive sleepiness during the day despite getting enough sleep at night.
Individuals with hypersomnolence disorder may experience difficulty staying awake during activities such as work, school, or driving. The disorder can interfere with daily activities and cause significant impairment in social, occupational, or other areas of functioning. The exact causes of hypersomnolence disorder are not well understood, but it may be related to a variety of factors, including genetics, neurological conditions, and psychological factors. 
Treatment for hypersomnolence disorder typically involves a combination of lifestyle modifications, such as improving sleep hygiene and regular exercise, and medication to promote wakefulness during the day. If you or someone you know is experiencing excessive daytime sleepiness, it is important to seek the help of a healthcare professional as soon as possible to diagnose and treat the condition.