To the Editor: Premenstrual syndrome (PMS) is a common phenomenon characterized by mental and physical symptoms preceding menstruation. The symptomatology of PMS includes the depression symptom present in many severe cases, and there is a correlation between the severity of psychological and physical symptoms. However, there have been few studies on the association of menstrual cycle abnormalities with female hormones and indices of biological responses in evaluating stress and depressive symptoms. In this study, we investigated the association of the menstrual cycle with depressive symptoms and measured urinary 8-hydroxydeoxyguanosine (u-8-OH-dG) and serum serotonin levels.

The participants were 24 female students with a normal menstrual cycle (mean=20.2 years old, SD=0.9). The menstrual cycle was identified and divided into early (within 3 days before the beginning of menstruation, middle (13–15 days after the beginning of menstruation), and late (26–28 days after the beginning of menstruation) phases. We used the State-Trait Anxiety Inventory Form X (STAI) and the Self-Rating Depression Scale (SDS) questionnaires for psychological tests. We measured u-8-OH-dG and s-serotonin levels in the three phases. The participants were divided into a depressive symptom group (n=11) and a healthy comparison group (n=13). A participant was added to the depressive symptom group when her SDS score of 40 points or higher persisted for 2 weeks or longer, when depressive symptoms were noted, or when the possibility of depression was high on review by our medical study group, which included a psychiatrist. The Student t-test was used for comparison between the groups, and the association between the SDS scores and s-serotonin and u-8-OH-dG levels was analyzed using Pearson's correlation.

No significant difference was noted in the s-serotonin or u-8-OH-dG level between the groups in any menstrual phase. Meanwhile, the SDS and STAI scores were strongly correlated in the late menstrual phase (r=0.687, p=0.009) in the depressive symptom group. The data suggest that PMS is severe and anxiety is marked in depressive symptom groups. The SDS score in the late menstrual phase was correlated with the total u-8-OH-dG (r=0.580, p=0.045) and s-serotonin levels (r=0.596, p=0.031) in the depressive symptom group. The depressive group was sensitive to stress, resulting in possible DNA injury, which may have enhanced the u-8-OH-dG level.² Mood-regulatory neurotransmitters, mainly serotonin, may have caused depressive symptoms.³ These may have caused the changes in hormone secretion, interacting with serotonin and producing differences in hormonal sensitivity.