Researchers from SciLifeLab, Uppsala University, Karolinska Institutet and Umeå University have investigated a new possible treatment for Premenstrual Dysphoric Disorder (PMDD), a psychiatric disorder triggered by hormonal changes during the menstrual cycle. The new treatment involves a specific progesterone receptor modulator that blocks progesterone receptors in the brain.

It is well known that the menstrual cycle can cause general discomfort and affect women’s mood. Most women, of reproductive age, experience only mild symptoms but for around 3-5 percent, the hormonal changes can lead to disabling mental symptoms, also known as premenstrual dysphoric disorder (PMDD).

Selective progesterone receptor modulators can bind to and inhibit progesterone receptors in the brain. These belong to a relatively new class of drugs that are also used to treat uterine fibroids.

In a recent multi-centered, double-blind, placebo-controlled clinical trial, SciLifeLab Fellow Erika Comasco (UU) and researchers from Uppsala University, Karolinska Institutet and Umeå University, have, for the first time, shown the efficacy of a selective progesterone receptor modulator when treating PMDD.

The results, published in the American Journal of Psychiatry, shows that the treatment primarily reduces mental symptoms, such as irritability and depression. Half of the treated women experienced a complete recovery while 21 percent of the women, receiving placebo, felt the same improvement.

“The side effects were mild and the ongoing development of well tolerated progesterone receptor modulators will hopefully make this a treatment option for patients with PMDD,” says Professor Inger Sundström-Poromaa (UU/WoMHeR), in a press release from Uppsala University.

Currently, the researchers are investigating how this progesterone receptor modulator affects the brain of women with PMDD. By using magnetic resonance imaging (MRI) and neuroimaging the brain before and during treatment, the researchers hope to be able to define structural and functional brain signatures that can explain the relief of PMDD symptoms.

The findings of this study provide vital information needed to reveal the mechanisms behind PMDD. Today, serotonin reuptake inhibitors are used as a treatment for PMDD and even if they are very effective, they still cause many side effects and are not suitable for all women. A new drug, without those disadvantages, that could more specifically target the mechanisms behind PMDD is therefore needed.