Patients with premenstrual syndrome have a different sensitivity to a neuroactive steroid during the menstrual cycle compared to control subjects.

We have evaluated the functional sensitivity to a neuroactive steroid in 12 women with and 12 women without premenstrual syndrome (PMS) at two stages of the menstrual cycle, by comparing the effects of three increasing doses of intravenous pregnanolone (3alpha-hydroxy-5beta-pregnan-20-one) on saccadic eye velocity (SEV) and self-rated sedation. Control subjects in the follicular and luteal phase showed a significant reduction in SEV after pregnanolone injections compared to vehicle. In PMS patients, pregnanolone injections induced a significant dose-related decrease in SEV compared to vehicle only in the follicular phase, not in the luteal phase. After pregnanolone injections, sedation scores increased significantly from vehicle among control subjects in the luteal phase but not among PMS patients in either cycle phase. High-severity PMS patients responded with less decrease in SEV and less increase in sedation scores following pregnanolone injections compared to low-severity patients. Control subjects increased their SEV response to pregnanolone in the luteal phase compared to the follicular phase, whereas PMS patients did not. These findings are compatible with a decreased GABAA-receptor sensitivity in brain areas controlling saccadic eye movements among PMS patients in the late luteal phase.