July 24 (HealthDay News) -- Scientists have discovered a gene variant linked to an increased risk of severe premenstrual depression.

Premenstrual dysphoric disorder, or PMDD, is a psychiatric condition that affects about 8 percent of women in their childbearing years. Women with PMDD experience bouts of major depression and/or anxiety and severe irritability during the second half of their menstrual cycle. These symptoms subside with the onset of the menstrual period.

PMDD has been thought to be related to hormonal changes over the course of the menstrual cycle.

For a new study published online June 30 in Biological Psychiatry, researchers studied 91 women with a confirmed diagnosis of PMDD over at least three months. Another 56 women who had no history of mood disorders related to the menstrual cycle served as the comparison group.

The team found four specific gene variants in the estrogen receptor alpha gene, ESR1, that were more common in the women with PMDD than in the control group.

"While these are preliminary findings that require replication in larger studies, we would argue that this may explain part of the variance among women in the susceptibility to developing this mood disorder," the study's senior author David R. Rubinow, Meymandi distinguished professor and chair of psychiatry at the University of North Carolina School of Medicine, said in a prepared statement.