Crying and laughing disorder is a condition in which the patient himself cannot control his emotions, sometimes laughing and sometimes crying, and is unpredictable. This disease may be due to problems in the brain and can be treated in the neurology and psychiatry departments of hospitals. The cause of crying and laughing disorder is mainly a disorder of brain function, abnormal mental activity, and may also be due to the effect of certain stimulants. Reactive psychosis is a common cause of crying and laughing disorder. Reactive psychosis is directly caused by intense or continuous stressful mental stimuli. The main components of its clinical manifestations are closely related to trauma and are accompanied by corresponding emotional experiences that are easily understood. Once the causative factors are eliminated or the environment is changed, and with appropriate treatment, the mental state can return to normal. Therefore, the prognosis of reactive psychosis is good, and relapse is usually not repeated. Diagnostic points of crying and laughing disorder caused by reactive psychosis: 1. Strong transient or persistent mental stimuli, appearing within a few days to 3 months before the onset of the disease. 2. There are sensitive, nervous and unstable qualities. 3. Clinical symptoms directly reflect or reenact the content of the traumatic situation. 4. Complete remission can be obtained rapidly after the elimination of the stimulus, improvement of adaptation ability or change of environment.