Idiopathic hypersomnia is a primary sleep disorder of central nervous system origin. It is an uncommon sleep disorder. However, it impacts patients significantly in their day to day activity. It is seen less frequently than narcolepsy. It is described clinically with excessive daytime sleepiness, often prolonged episodes of non-refreshing sleep, prolonged naps and difficulty in awakening from sleep. The difficulty awakening from sleep is often labeled as “sleep drunkenness”. At this time, the pathophysiology of this disorder is not well understood. It is very important to exclude other potential causes and therefore is a diagnosis of exclusion. Treatment for this disorder is in the similar algorithm as patients with narcolepsy; however the response is not consistent. Therefore, this specific disorder is one of the frustrations for most clinicians who treat these patients. This section will review the epidemiology, pathogenesis, clinical features, diagnostic criteria, differential diagnosis, treatment and future outlook of this frustrating disorder.
