People usually spend 1/3 of the day and night sleeping, i.e., they go to sleep at night and wake up during the day, forming a sleep-wake rhythm. Sleep-wake rhythm disorders are sleep disorders caused by a sleep-wake rhythm that is different from the usual one. The disorder is usually seen in adults, but is rarely seen in childhood or adolescence. The diagnosis of sleep-wake rhythm disorder is based on the following points: 1. The patient’s sleep-wake rhythm is not in accordance with what is required (i.e. with the social requirements of the patient’s environment and the rhythm followed by most people); 2. The patient has insomnia during the main postoperative sleep period and drowsiness during the waking hours when he/she should be awake; 3. 5. Secondary sleep-wake rhythm disorders due to physical illness or psychiatric disorders (e.g., depression) have been excluded.