Background. Neurosteroids such as allopregnanolone and pregnanolone are suggested to be of importance for the pathophysiology of premenstrual dysphoric disorder. The aim of this study was to investigate whether the luteal-phase serum concentrations of these neurosteroids are associated with improvement of premenstrual symptoms in 12 women with severe premenstrual syndrome after treatment with low-dose gonadotropin-releasing hormone agonist and placebo.

Methods. Daily ratings for mood and physical symptoms were made prior to treatment and throughout the study. Serum progesterone, allopregnanolone and pregnanolone were assessed in the luteal phase (cycle day -9 to cycle day -1). Based on their symptom ratings, subjects were grouped as either buserelin responders (n = 6) or placebo responders (n = 6).

Results. Buserelin responders displayed decreased levels of allopregnanolone (p < 0.05) and progesterone (p < 0.05) in parallel with improvement of symptoms. During the placebo treatment, the placebo responders had lower serum allopregnanolone concentrations than buserelin responders (p < 0.05). This was associated with improvement in symptoms compared with pre-treatment ratings.

Conclusion. Treatment response, whether induced by buserelin or placebo, appears to be associated with a decrease in allopregnanolone concentration.