What is Hypersomnolence Disorder?

The video describes Hypersomnolence Disorder. Hypersomnolence Disorder is characterized by excessive sleepiness even when the main sleep period has been at least seven hours. There are several symptoms for Hypersomnolence Disorder in the Diagnostic and Statistical Manual including recurrent periods of sleep or lapses into sleep, a main sleep period of nine hours or more without feeling refreshed, not feel fully awake after being abruptly awakened (sleep inertia, sleep drunkenness). The symptoms cannot be better explained by another sleep disorder, medical condition, or another condition like substance use. The prevalence of Hypersomnolence Disorder is about 1%.