Glossary

idiopathic hypersomnia [IH]

Idiopathic hypersomnia (IH) is a long-lasting (chronic) sleep disorder of the brain (neurologic disorder). It affects the brain’s ability to control sleep and wakefulness and causes excessive daytime sleepiness (EDS). Other symptoms may include brain fog, sleep drunkenness (or severe sleep inertia), and long unrefreshing naps. Read more on our IH web page.

Idiopathic hypersomnia is defined by the International Classification of Sleep Disorders (ICSD). Hypersomnolence disorder is the most similar diagnosis defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM). Read more on our web page for doctors “Diagnosis, classification, symptoms, and causes of hypersomnias.”