These symptoms may affect performance on perception, memory, learning, executive functions, language, constructive abilities, voluntary motor control, attention, and mental speed. Affected individuals can complain of forgetfulness, confusion, or inability to think clearly. Excessive sleep (9 hours or more over a full 24-hour period), without feeling refreshed after waking. Daytime naps can be up to several hours and are also unrefreshing.Some studies have shown increased frequencies of palpitations, digestive problems, difficulty with body temperature regulation, and other symptoms in patients with IH. Anxiety and depression are frequent, likely as a response to chronic illness. A case series in 2010 found that peripheral vascular symptoms, such as cold hands and feet (e.g., Raynaud Syndrome), were more common in people with IH than in controls.Other autonomic dysfunctional symptoms, such as fainting episodes, dizziness upon arising, headaches (possibly migrainous in quality), food cravings, and impotence may also be correlated with IH. Researchers have found that people reporting IH symptoms report high levels of autonomic dysfunction on par with other conditions of autonomic failure (i.e., MSA and diabetes). As of June 2021, there is no evidence to suggest such symptoms are related to IH in any way. Causes
Unlike narcolepsy with cataplexy, which has a known cause (autoimmune destruction of hypocretin-producing neurons), the cause of IH is largely unknown.
CNS stimulants tend to be less effective for IH than they are for narcolepsy and may be less well tolerated. Stimulants
The main treatment of excessive daytime sleepiness is done through central nervous system stimulants. Methylphenidate and Dextroamphetamine are most used stimulants to controlled EDS. Increased dopamine release is felt to be the main property explaining wake-promotion from these medications. Insomnia is another common side effect and may require additional treatment. Non-stimulant wake-promoting medications
Solriamfetol is the first and only dual-acting dopamine and norepinephrine reuptake inhibitor approved by the FDA to improve wakefulness in adults living with excessive daytime sleepiness associated with narcolepsy or obstructive sleep apnea.Pitolisant, a selective histamine 3 (H3) receptor antagonist/inverse agonist, was approved by FDA during August 2019. It works by increasing the synthesis and release of histamine, a wake-promoting neurotransmitter in the brain. Modafinil and Armodafinil elevate hypothalamic histamine levels, and they are known to bind to the dopamine transporter, thereby inhibiting dopamine reuptake. Modafinil can cause uncomfortable side effects, including nausea, headache, and a dry mouth for some patients, while other patients report no noticeable improvement even on relatively high dosages. They may also "interact with low-dose contraceptives, potentially reducing efficacy, although the scientific data supporting this claim is weak and rests on poorly documented anecdotes." Sleep promoting medications
Sodium oxybate is an orphan drug which was designed specifically for the treatment of narcolepsy. Common side effects include nausea, dizziness, and hallucinations. A 2016 study by Leu-Semenescu et al.