Objectives : A large of studies have found an association between premenstrual syndrome and affective disorder, in particular, depression. Some studies have reported that women with depressive disorders may experience menstrual cycle-associated changes in the severity of their symptoms. This study was designed to compare the characteristics of premenstrual changes between control group and affective patient group, and to assess possible risk factors for premenstrual changes in patients. Methods : Eighty normal controls and eighty outpatients given maintenance therapy with fixed dose for at least more than four weeks were asked to complete questionnaires on menstrual history, obstetric-gynecological history, and functional impairment. In addition, to compare the characteristics of premenstrual changes, 16 items based on DSM-IV criteria A for premenstrual dysphoric disorder were rated on the following scale : 0(no change), 1(mild), 2(moderate), 3(severe). Moderate or severe change in each item was considered as premenstrual change and the subjects who reported more than one premenstrual change were defined as premenstrual change group. Results : The results were as follows : 1) The percentage of premenstrual change group was 32.6% in patient group and 50% in control group. 2) Frequently reported premenstrual changes were as follows in control group : breast tenderness; anger ; affective liability ; lethargy, easy fatigability, or marked lack of energy ; abdominal pain or discomfort. In patients, the mood or behavioral changes were frequently reported. The changes were as follows : lethargy, easy fatigability, or marked lack of energy ; change in appetite; affective liability ; sense of difficulty in concentrating : hypersomnia or insomnia. 3) In the premenstrual change group, the patients with only mood or behavioral changes were significantly more than those with only physical changes or both changes. 4) The severity of functional impairment was significantly correlated with the frequency of mood or behavioral changes in patients. 5) There were no significant differences in menstrual characteristics between patients with premenstrual changes and patients without them except the severity of dysmenorrhea. And the severity of dysmenorrhea was correlated with the frequency of premenstrual change. Conclusion : The proportion of patients with affective disorder, who reported moderate-to-severe premenstrual changes, experiencing mood or behavioral changes larger than those experiencing physical changes during premenstrual period. It is possible that some patients with affective disorder, who reported premenstrual mood or behavioral changes, suffer from coexisting premenstrual syndrome with affective disorder or premenstrual exacerbation of affective disorder. Since the more premenstrual changes, the severer functional impairment, the patients reporting mood or behavioral disturbance in premenstrual period should be carefully evaluated, and appropriate therapeutic stategies might be considered.