If an adult suddenly becomes drowsy recently, the following possibilities should be considered: 1. If the patient is drowsy with symptoms such as fear of cold and facial swelling, the above discomfort caused by hypothyroidism should be considered. 2. If the patient is drowsy with depressed mood, loss of appetite and other symptoms, the above discomfort caused by depression should be considered. 5. Consider the condition of apnea during sleep at night which leads to brain hypoxia and causes drowsiness the next day. However, it is recommended to see a neurologist at the hospital to make a clear diagnosis of the above conditions.