Insomnia refers to the inability to fall asleep or to stay asleep, resulting in sleep deprivation. It is a condition characterized by frequent failure to obtain normal sleep, for various reasons such as difficulty in falling asleep, short sleep depth or frequency (light sleep insomnia), early awakening and insufficient sleep time or poor quality sleep. So, what causes insomnia? Here are some of the causes of insomnia. 1, insomnia caused by physiology: changes in the environment can cause physiological reactions, such as changes in the sleep environment when riding in cars, boats and airplanes; strong light, noise, too cold or too hot in the bedroom may make people insomnia. Some people have strong adaptability to the environment, while others are very sensitive and poorly adapted, and sleep poorly when the environment changes. 2, taking drugs and other substances caused by insomnia: taking central excitatory drugs can lead to insomnia, such as diet pills amphetamines. Long-term use of sleeping pills, once you quit, you will also experience withdrawal symptoms – shallow sleep, more nightmares. Tea, coffee, cola-type drinks, etc. contain central nervous stimulants – caffeine, which can cause insomnia when consumed in the evening. Alcohol interferes with a person’s sleep structure, making sleep shallow, and once you quit drinking alcohol can also cause insomnia due to withdrawal reactions. 3, insomnia caused by psychological and mental factors: psychological factors such as anxiety, irritability or depression, unhappy mood, etc., are important causes of insomnia. The blow of life, the pressure of work and study, the attempted will and the change of social environment can cause psychological and physiological reactions, resulting in abnormal function of the nervous system, causing dysfunction of the brain, thus causing insomnia. 4, insomnia caused by physical diseases: physical diseases of insomnia include heart disease, kidney disease, asthma, ulcer disease, arthritis, osteoarthritis, gastrointestinal disease, hypertension, sleep apnea syndrome, hyperthyroidism, nocturnal myoclonus syndrome, brain disease, etc. Some people expect too much from sleep and believe that if you sleep well, your body will not be invaded by all kinds of diseases, but if you sleep badly, you will be prone to various physical problems. This excessive superstition about sleep increases the pressure of sleep and can easily cause insomnia. People inevitably have bad sleep, but some people are too worried about this temporary bad sleep and its impact on the body, the thought of sleep, will be conditioned to fear, always thinking about the need to sleep well, but make it more difficult to fall asleep. This will form a vicious circle of fear of insomnia – committed to sleep – insomnia – more fear of insomnia. In the long run, it is likely to evolve into chronic insomnia.