5α-Reductase Inhibition Prevents the Luteal Phase Increase in Plasma Allopregnanolone Levels and Mitigates Symptoms in Women with Premenstrual Dysphoric Disorder

The study investigated the effect of the 5α-reductase inhibitor dutasteride on neurosteroid levels and symptoms in women with premenstrual dysphoric disorder (PMDD). Sixteen women with PMDD and 16 control women participated in randomized, double-blind, placebo-controlled, cross-over trials. The high-dose dutasteride group (2.5 mg/day) showed a significant reduction in PMDD symptoms such as irritability, sadness, anxiety, food cravings, and bloating, while the low-dose group (0.5 mg/day) did not show significant effects. Dutasteride did not affect mood in control women. The findings suggested that stabilizing allopregnanolone levels by inhibiting its conversion from progesterone could mitigate PMDD symptoms, highlighting the role of neurosteroids in this condition.