--- title: Does a hormone called allopregnanolone calm the body's startle reaction in PMDD? description: No. Giving this hormone by injection made women feel more sedated but did not change their physical startle response, in either women with PMDD or healthy wom url: https://niyora.com/research/papers/allopregnanolone-has-no-effect-on-startle-response-and-prepulse-inhibition-of-2009/ --- - [Niyora](https://niyora.com/) - [Research](https://niyora.com/research/) - [Library](https://niyora.com/research/library/) - Does a hormone called allopregnanolone calm the body's startle reaction in PMDD? Randomised trial, 2009 # Does a hormone called allopregnanolone calm the body's startle reaction in PMDD? No. Giving this hormone by injection made women feel more sedated but did not change their physical startle response, in either women with PMDD or healthy women. Early or limited evidence 16 women with PMDD and 12 healthy women without PMDD. ## What they did A small double-blind, randomized study tested 16 women with PMDD and 12 healthy women. Each woman received an intravenous injection of allopregnanolone and, 48 hours apart, a placebo injection, during the luteal phase. Startle response (a muscle reflex to sudden noise) and how well it was filtered out (prepulse inhibition) were measured with electrodes. ## What they found The injection raised allopregnanolone blood levels to 50-70 nmol/l, similar to levels in pregnancy. Women with PMDD had significantly lower allopregnanolone levels than healthy women (p<0.05). Both groups felt more sedated after the hormone injection than placebo (p<0.01), but the injection did not change the startle response or its filtering, and there was no difference between the PMDD and healthy groups. ## What it means for you A single dose of this hormone made women feel drowsy but did not reduce the measured startle reflex, so this particular calming effect was not confirmed. The study was small and looked at a lab measurement, not everyday mood symptoms. 16 / 12 Women with PMDD / healthy controls 50-70 nmol/l Allopregnanolone blood level reached p<0.01 Sedation increase (both groups) ## About the study Original title Allopregnanolone has no effect on startle response and prepulse inhibition of startle response in patients with premenstrual dysphoric disorder or healthy controls Authors Kask K, Bäckström T, Lundgren P et al. Journal Pharmacology, biochemistry, and behavior Year 2009 Study design Randomised trial What was tested Single intravenous injection of allopregnanolone compared with placebo. Read the paper [doi.org/10.1016/j.pbb.2009.02.014](https://doi.org/10.1016/j.pbb.2009.02.014) ## Topics [Premenstrual syndrome (PMS)](https://niyora.com/research/topics/condition-pms/)[Premenstrual dysphoric disorder (PMDD)](https://niyora.com/research/topics/condition-pmdd/)[Low mood and depression](https://niyora.com/research/topics/symptom-depression-mood/)[Anxiety and tension](https://niyora.com/research/topics/symptom-anxiety/)[Cognition, concentration and memory](https://niyora.com/research/topics/symptom-cognition/)[Neurosteroids (allopregnanolone)](https://niyora.com/research/topics/treatment-neurosteroids/)[Pregnancy and postpartum](https://niyora.com/research/topics/comorbidity-postpartum/)[Epilepsy](https://niyora.com/research/topics/comorbidity-epilepsy/) Research tells you what helps on average. Niyora helps on the day it hits. Calm down, see it another way, and decide what to say, with a PMS and PMDD app built by a doctor. ## Related studies Review, 2003 How do menstrual cycle hormones affect the brain and cause mood disorders like PMDD? Lab study, 2013 Could antidepressants help prevent PMS by keeping brain chemicals stable? Review, 2004 Could a brain hormone called allopregnanolone explain mood problems like PMDD in women? Survey study, 2000 Why do women get more anxious when hormone levels drop? Randomised trial, 2017 Does Sepranolone reduce symptoms of severe premenstrual syndrome (PMDD)? Case-control study, 2013 Are stress hormones different in women with PMDD? Ask AI about this page Copy prompt ChatGPT ↗ Claude ↗ Perplexity ↗ Google AI Mode ↗ Grok ↗