The main mental symptoms of hypothyroidism are fatigue, weakness, little speech, laziness, little movement, unresponsiveness, memory loss and other hypometabolic symptoms. Hypothyroidism is caused by the lack of thyroid hormones in the blood. Thyroid hormones can participate in a variety of material metabolism and energy metabolism processes in the body, promote increased heat production, and also affect the development of the nervous system. Therefore, thyroid hormone deficiency not only causes symptoms of hypometabolism such as mucinous edema, weight gain and slower heart rate in the body. It can also manifest as mental and neurological symptoms such as decreased memory and comprehension, fatigue, weakness, less speech, laziness, slowness of reaction, slow movement, etc. Hypothyroidism in infants and children can also lead to cretinism. The neurological symptoms of hypothyroidism are related to thyroid hormone deficiency. When hypothyroid patients are given appropriate treatment and their thyroid function is restored to normal, the mental symptoms of hypothyroidism will improve on their own.