1. ¹Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
2. ²Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, USA
3. ³Department of Clinical Science, Obstetrics and Gynecology, Umeå University, Umeå, Sweden
4. ⁴Department of Psychiatry, University of California, San Diego, CA, USA

Correspondence: Dr K Kask, Department of Women's and Children's Health, Uppsala University, University Hospital, Uppsala SE-751 85, Sweden, Tel: 46186113174; Fax: 4618559775; E-mail: kristiina.kask@kbh.uu.se

Received 28 June 2007; Revised 17 September 2007; Accepted 19 September 2007; Published online 17 October 2007.

Abstract

Patients with premenstrual dysphoric disorder (PMDD) experience their most intense symptoms during the late luteal phase. The aim of the current study was to compare acoustic startle response and prepulse inhibition in PMDD patients and controls during the follicular and late luteal phases of the menstrual cycle. Following two months of prospective daily ratings on the Cyclicity Diagnoser scale, 30 PMDD patients and 30 asymptomatic controls, between the ages of 20 and 46, were included in the study. The eyeblink component of the acoustic startle reflex was assessed using electromyographic measurements of m. orbicularis oculi. Twenty pulse-alone trials (115 dB 40 ms broad-band white noise) and 40 prepulse–pulse trials were presented. The prepulse stimuli consisted of a 115 dB 40 ms noise burst preceded at a 100 ms interval by 20 ms prepulses that were 72, 74, 78, or 86 dB. PMDD patients had a significantly higher startle response than controls during both phases of the menstrual cycle (p<0.05). PMDD patients exhibited lower levels of prepulse inhibition with 78 dB and 86 dB prepulses compared to control subjects in the luteal (p<0.01) but not in the follicular phase. Whereas control subjects displayed increased PPI during the late luteal phase compared to the follicular phase (p<0.01), PPI magnitude remained unchanged in PMDD patients between cycle phases. Relative to controls, PMDD patients displayed increased startle reactivity across both menstrual cycle phases and deficits in prepulse inhibition of acoustic startle during the late luteal phase. These findings are consistent with an altered response to ovarian steroids among PMDD patients.