Sleep Disorders Insomnia & More Disorders The Difference Between Narcolepsy Type 1 and 2 By Brandon Peters, MD Brandon Peters, MD Facebook Twitter Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist. Learn about our editorial process Updated on May 25, 2022 Medically reviewed by Jason DelCollo, DO Medically reviewed by Jason DelCollo, DO Jason DelCollo, DO, board-certified in family medicine. He is associate faculty at Philadelphia College of Osteopathic Medicine as well as adjunct faculty with the Crozer Family Medicine Residency Program, and is an attending physician at Glen Mills Family Medicine in Glen Mills, Pennsylvania. Learn about our Medical Expert Board Print Narcolepsy is always characterized by excessive daytime sleepiness, but there are other symptoms and test results that are used to differentiate the sub-types of the condition. There are two types of narcolepsy, but what is the difference between narcolepsy type 1 and type 2? Learn about these differences, including the role of cataplexy and testing for hypocretin levels in the cerebrospinal fluid (CSF). AntonioGuillem / iStock / Getty Images Symptoms of Narcolepsy May Differentiate Sub-Types Both types of narcolepsy include an irrepressible need to sleep or daytime lapses into sleep. Without sleepiness, narcolepsy is not a proper diagnosis. There are some other associated symptoms, and some of these can help to differentiate the sub-types. There are two types of narcolepsy—type 1 and type 2. Type 1 may include the presence of the symptom of cataplexy. Cataplexy is defined as more than one episode of brief, usually symmetrical sudden loss of muscle tone with retained consciousness. This weakness may be provoked by strong emotions. These emotions are usually positive; for example, cataplexy may be associated with laughter. The weakness may involve the face, arms, or legs. Some narcoleptics will have droopy eyelids, mouth opening, tongue protrusion, or head bobbing. Some people can collapse to the ground during an attack of cataplexy. Both types of narcolepsy may also include sleep paralysis and hypnagogic hallucinations. Fragmented sleep at night often occurs in both conditions as well. The Role of Testing for Hypocretin and the MSLT Specific testing can also be used to differentiate between the two sub-types of narcolepsy. Excessive daytime sleepiness is determined based on the results of a multiple sleep latency test (MSLT). This test follows a standard sleep study and includes four or five nap opportunities that occur at 2-hour intervals. The subject is given an opportunity to sleep, and people with narcolepsy will fall asleep in less than 8 minutes on average. In addition, REM sleep will occur within 15 minutes of sleep onset in at least two of the nap opportunities. Moreover, testing of the hypocretin levels in the CSF fluid as part of a lumbar puncture can be revealing. If the levels are measured to be less than 110 pg/mL, this is consistent with a diagnosis of type 1 narcolepsy. If the levels are normal (or not measured) and cataplexy is not present, type 2 narcolepsy is diagnosed if the MSLT is positive. If the hypocretin level is measured to be abnormal later, or if cataplexy subsequently develops, the diagnosis can be changed to type 1. Though narcolepsy is a rare condition, it occurs commonly enough, with type 1 affecting about one in 5,000 people. The diagnosis should be made by a sleep specialist who is able to apply the proper testing and subsequently provides effective treatment. If you are concerned that you may have symptoms of narcolepsy, seek further evaluation by a sleep expert who can provide you the care and support that you need. 2 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Golden EC, Lipford MC. Narcolepsy: diagnosis and management. Cleve Clin J Med. 2018;85(12):959-969. doi:10.3949/ccjm.85a.17086 Kallweit U, Schmidt M, Bassetti CL. Patient-reported measures of narcolepsy: The need for better assessment. J Clin Sleep Med. 2017;13(5):737–744. doi:10.5664/jcsm.6596 Additional Reading American Academy of Sleep Medicine. International Classification of Sleep Disorders, 3rd ed. Darien, IL: American Academy of Sleep Medicine. By Brandon Peters, MD Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit