Objective: The relationship between emotional stress and the onset of hyperthyroidism has been well investigated, but the relationship between psychological factors and prognosis of antithyroid drug-treated hyperthyroidism is not well known. This study has examined not only emotional stresses but also patients' personality traits using specific tests.
Design: A prospective cohort study.
Subjects: Sixty-nine patients with hyperthyroid Graves' disease in the euthyroid state after 2-5 years of antithyroid drug therapy and 32 healthy subjects as the control group.
Measurements: Patients responded to three types of questionnaires, including the Minnesota Multiphasic Personality Inventory for personality traits, the Natsume's Stress Inventory for major life events, and the Hayashi's Daily Life Stress Inventory for daily life stresses.
Results: In the Graves' disease patients, stress scores of life events correlated significantly with serum TSH receptor antibody activity (r = 0.424, P < 0.001) and thyroid volume (r = 0.480, P < 0.001). When the patients were divided according to prognosis (41 with relapse and 28 with remission), four personality traits including hypochondriasis, depression, paranoia and psychasthenia (mental fatigue) were significantly (P = 0.0146, 0.0052, 0.0125, and 0.0186, respectively) more common in the relapsed Graves' disease group than those of the remitted group. Six personality traits of conversion hysteria, psychopathic deviation, masculinity and feminity, schizophrenia, hypomania, and social introversion were not significantly different between the two groups. The scores of daily hassles (problems of daily life) were also significantly (P = 0.0124) greater in the relapsed Graves' disease group than in the remitted group. The scale scores of depression and psychasthenia showed a positive correlation with scores of daily hassles (r = 0.535, P < 0.0001; r = 0.580, P < 0.0001, respectively), while an inverse correlation with scores of daily uplifts (r = -0.373, P = 0.0332; r = -0.322, P = -0.0120, respectively).
Conclusions: The results suggest that major life events, personality traits of hypochondriasis and depression, paranoia, mental fatigue, and daily problems aggravate the prognosis of antithyroid drug-treated hyperthyroidism. Escape from life events is virtually impossible; thus coping strategies suggested by the physician may be useful in improving prognosis in Graves' disease.