Mood instability in women with premenstrual syndrome.

OBJECTIVE: Most women of reproductive age experience premenstrual symptoms. Mood swings within a day and from day to day are a common complaint of people with mood problems (mood instability). We investigated whether mood instability was higher in women with premenstrual syndrome (PMS) than in a control group with no PMS.
METHODS: We prospectively studied mood and physical symptoms over two menstrual periods in 29 women with self-identified PMS and 31 women without PMS. We excluded women on hormonal birth control or with a history of past or current diagnoses of depression. We used the mean square successive difference derived from twice daily visual analogue scale ratings of mood as the measure of mood instability.
RESULTS: The women with PMS showed more irritable and depressed mood instability than the women without PMS. These differences were present whether or not the late luteal phase (seven days before the start of menstruation) was included in the data. On visual inspection of mood ratings, typically irritable and depressed moods increased in the late luteal phase. However, women with self-identified PMS showed a variety of mood patterns throughout the cycle.
CONCLUSION: Women with PMS have increased mood instability within the seven day premenstrual phase and at other times as well. This supports the premise that PMS may represent a manifestation of an underlying problem of mood dysregulation in common with other mood disorders.