Idiopathic hypersomnia (IH) is a neurological disorder which is characterized primarily by excessive sleep and excessive daytime sleepiness (EDS). The condition typically becomes evident in early adulthood and most patients diagnosed with IH will have had the disorder for many years prior to their diagnosis. As of August 2021, an FDA-approved medication exists for IH, in addition to several off-label treatments (primarily FDA-approved narcolepsy medications).Idiopathic hypersomnia may also be referred to as IH, IHS, or primary hypersomnia and belongs to a group of sleeping disorders known as central hypersomnias, central disorders of hypersomnolence, or hypersomnia of brain origin. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) defines idiopathic hypersomnia as EDS without narcolepsy or the associated features of other sleep disorders. It occurs in the absence of medical problems or sleep disruptions, such as sleep apnea, that can cause secondary hypersomnia. Signs and symptoms
Individuals with IH share common symptoms like excessive daytime sleepiness, sleep inertia, brain fog, long sleep periods, and others. Excessive daytime sleepiness, characterized by persistent sleepiness throughout the day and often a general lack of energy—even during the day after apparently adequate or even prolonged nighttime sleep. People with EDS nap repeatedly throughout the day and have strong urges to sleep while driving, working, eating, or conversing with others. Sleep inertia (also known as sleep drunkenness), characterized by having extreme difficulty waking up and feeling an uncontrollable desire to go back to sleep. Clouding of consciousness characterized by inattention, thought process abnormalities, comprehension abnormalities, and language abnormalities.
found sodium oxybate reduced daytime sleepiness in IH to the same degree as in patients with narcolepsy type 1, and the drug improved severe sleep inertia in 71% of the hypersomnia patients. In July 2020, the FDA approved Xywav™ (calcium, magnesium, potassium, and sodium oxybates), an oral solution for the treatment of cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy. Cognitive Behavioral Therapy
Although behavioral approaches have not been demonstrated to improve clinical markers of IH, cognitive behavioral therapy has been found to potentially reduce depressive symptoms and improve self-efficacy in people with central disorders of hypersomnolence. Prognosis
IH can profoundly affect work, education, and quality of life due to excessive daytime somnolence. Patients will often need to adapt their lifestyle to avoid situations that might be dangerous while sleepy, such as high risk work, or driving. The risks associated with these activities have been found to be higher for patients with hypersomnias than for those with sleep apnea or severe insomnia. Epidemiology
Typically, the symptoms of IH begin in adolescence or young adulthood, although they can begin at a later age. After onset, hypersomnia often worsens over several years, but it is often stable by the time of diagnosis and appears to be a lifelong condition. Spontaneous remission is only seen in 10–15% of patients.According to the limited epidemiological data that exists, IH "has more of a female preponderance (1.8/1)." Family cases are frequent, in a range from 25% to 66% without any clear mode of inheritance.