Mental disorders merge highly with thyroid diseases. Because of its regulatory effects on serotonin and noradrenalin, T3 has been linked closely to depression and anxiety. It has known that in many cases, the mental symptoms persist even after normalization of thyroid function by treatment. Psychosocial factors including stress have been associated with mental symptoms even after thyroid function normalization in Graves' disease and a combination of mental disorders have been related to the exacerbation of hyperthyroidism. These findings suggest that psychosomatic approaches based on the bio-psycho-social medical model are important for the treatment of mental disorders associated with Graves' disease.