Is sleepiness hereditary?

Sleepiness is a functional disease. It often causes functional neurological disorders in the brain and nervous system because no lesions can be found. Common causes of sleepiness include irregular work and rest schedules and inflammatory diseases. Whether sleepiness is hereditary needs to be diagnosed. Generally, there is no genetic factor for this disease.

Pathological etiology

Narcolepsy is a functional disease, which means that no specific lesions can be found in other parts of the brain and nervous system. It may be caused by dysfunction of the cerebral cortex nerves.

Disease diagnosis

Narcolepsy, sleep apnea syndrome, and sleepiness caused by organic brain diseases or mental disorders need to be excluded.

1) Narcolepsy, which is usually accompanied by one or more additional symptoms, such as cataplexy, sleep paralysis, and hypnagogic hallucinations; the sleep attacks are irresistible; nocturnal sleep is fragmented and shortened, whereas hypersomnia attacks occur less frequently during the day but last longer; patients are often able to prevent them from occurring; and nocturnal sleep is usually prolonged.

2) Sleep apnea, that is, hypersomnia associated with sleep apnea. In addition to the symptoms of excessive daytime sleepiness, these patients also have nocturnal apnea, typical intermittent snoring, obesity, hypertension, cognitive impairment, nocturnal sweating and hyperactivity, morning headaches and a history of poor ataxia. The onset time and duration of apnea can be determined with the help of records in the sleep laboratory. The above are not difficult to distinguish from narcolepsy.

3) Organic diseases with narcolepsy, encephalitis, meningitis, concussion and other mental illnesses, metabolic disorders, poisoning, endocrine abnormalities, post-radiation syndrome, etc. can all cause narcolepsy. Through medical history, physical examination, clinical observation and corresponding laboratory tests, it can be clearly diagnosed that the narcolepsy is caused by an organic disease, then the diagnosis of (non-organic) narcolepsy should not be considered.

Hypersomnia can be diagnosed by tracking the typical stages of sleep and by doing an overnight sleep study with the multi-step sleep latency test (MSLTT). A sleep study looks for other causes of excessive daytime sleepiness, such as sleep deprivation, sleep apnea, and depression. The test is done at a sleep research institute, where researchers electronically monitor brain waves, eye movements, muscle activity, heart rate, blood oxygen levels, and breathing using a polysomnogram. The MSLTT is usually done after a good night's sleep so that the results are clearer. It is usually done after a sleep study.

The multiple-stage sleep latency test involves four 20-minute nap opportunities, spaced evenly throughout the day over a two-hour period. Sleepy people fall asleep in five minutes or less, and transition to REM (rapid eye movement) sleep occurs in at least two of the four naps. In contrast, normal people typically take 12 to 14 minutes to fall asleep and do not enter the REM sleep stage.