Bad sleep may be caused by the following conditions: first, because of abnormal brain nerve lesions, such as brain neurasthenia or brain nerve dysfunction, because the brain is very complex and rich in function, and plays a vital role in regulating the body’s sleep and wakefulness and biological clock. If a person’s brain nerve weakness or brain nerve dysfunction is unable to adjust the normal sleep and wake cycle in time, thus disrupting this cycle, there will always be poor sleep. Secondly, it may be caused by hypersensitivity or emotional agitation or depression, because people in a state of emotional agitation or depression may cause sympathetic excitation. The excitatory transmitters in the body, such as dopamine or adrenaline, norepinephrine levels rise, can cause abnormal brain discharge or brain cells in a state of continuous excitement, which can lead to poor sleep.