Narcolepsy is a chronic neurological disorder that impairs the ability to regulate sleep–wake cycles, and specifically impacts REM (rapid eye movement) sleep. The pentad symptoms of narcolepsy include excessive daytime sleepiness (EDS), sleep related hallucinations, sleep paralysis, disturbed nocturnal sleep (DNS) and cataplexy. There are two recognized forms of narcolepsy, narcolepsy type 1 and type 2. Narcolepsy type 1 (NT1) can be clinically characterized by symptoms of EDS and cataplexy, and/or will have CSF orexin levels of less than 110 pg/ml. Cataplexy are transient episodes of aberrant tone, most typically loss of tone, that can be associated with strong emotion. In pediatric onset narcolepsy, active motor phenomena are not uncommon. Cataplexy may be mistaken for syncope, tic disorder or seizures. Narcolepsy type 2 (NT2) does not have features of cataplexy and CSF orexin levels are normal. Sleep related hallucinations, also known as hypnogogic (going to sleep) and hypnopompic (on awakening) are vivid hallucinations that can be auditory, visual or tactile and may occur independent of or in combination with an inability to move (sleep paralysis). People with narcolepsy tend to sleep about the same number of hours per day as people without it, but the quality of sleep is typically compromised. Narcolepsy is a clinical syndrome of hypothalamic disorder, but the exact cause of narcolepsy is unknown, with potentially several causes. A leading consideration for the cause of narcolepsy type 1 is that it is an autoimmune disorder. Proposed pathophysiology as an autoimmune disease suggest antigen presentation by DQ0602 to specific CD4+ T cells resulting in CD8+ T-cell activation and consequent injury to orexin producing neurons. Familial trends of narcolepsy are suggested to be higher than previously appreciated. Familial risk of narcolepsy among first degree relatives is high. Relative risk for narcolepsy in a first degree relative has been reported to be 361.8. However, it is important to note that there is a spectrum of symptoms found in this study, including asymptomatic abnormal sleep test findings to significantly symptomatic. The autoimmune process is thought to be triggered in genetically susceptible individuals by an immune provoking experience, such as infection with H1N1 influenza. Secondary narcolepsy can occur as a consequence of another neurologic disorder. Secondary narcolepsy can be seen in some individuals with traumatic brain injury, tumors, Prader Willi Syndrome or other diseases affecting the parts of the brain that regulate wakefulness or REM sleep. Diagnosis is typically based on the symptoms and sleep studies, after excluding alternative caused of EDS. EDS can also be caused by other sleep disorders such as insufficient sleep syndrome, sleep apnea, major depressive disorder, anemia, heart failure, and drinking alcohol. While there is no cure, behavioral strategies, lifestyle changes, social support and medications may help. Lifestyle and behavioral strategies can include identifying and avoiding or desensitizing emotional triggers for cataplexy, dietary strategies that may reduce sleep inducing foods and drinks, scheduled or strategic naps and maintaining a regular sleep wake schedule. Social support, social networks, and social integration are resources that may lie in the communities related to living with narcolepsy. Medications used to treat narcolepsy are primarily targeting EDS and/or cataplexy. These medications include alerting agents (modafinil, armodafinil, pitolisant and solriamfetol), Oxybate medications (twice nightly sodium oxybate, twice nightly mixed salts oxybate and once nightly extended release sodium oxybate), and stimulants (methylphenidate and amphetamines). There is also the use of antidepressants, such as Tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), and selective norepinephrine reuptake inhibitors (SNRIs) for the treatment of cataplexy. Estimates of frequency range from 0.2 to 600 per 100,000 people in various countries. The condition often begins in childhood, with males and females being affected equally. Untreated narcolepsy increases the risk of motor vehicle collisions and falls. Narcolepsy generally occurs anytime between early childhood and 50 years of age, and most commonly between 15 and 36 years of age. However, it may also rarely appear at any time outside of this range. Source: Wikipedia (en)