PMS Causes Abnormal Patterns In The Brain

Anh Nguyen/Unsplash

An examination of the extent ovarian hormones affect neural activity in women with PMS.

By Patrick James Hibbert 

16 Dec 2019

To investigate the neural mechanism behind premenstrual syndrome (PMS), researchers from Beijing Normal University’s School of Psychology in Beijing, China, conducted a study by giving a series of self-reporting tests and a functional MRI (fMRI) to women with and without PMS. 

The fMRI measured signals related to blood flow and oxygenation. While the self-reporting tests were used for the detection of anxiety, depression, and stress. Conclusively, the tests showed that women with PMS had higher anxiety, depression, and stress. All of which correlated with abnormal neural patterns found in their brain from their fMRIs. What's more, is that the scientists discovered the abnormalities lie in an area of their brains called the Default Mode Network (DMN).

All of the women in the study were tested once in two different menstrual cycle phases. Amongst the tests they took was the Beck Anxiety Inventory, to measure their levels of anxiety. It’s a 21 question, multiple-choice, self-report inventory. 

This inventory gives a value between 0 and 3 for each question and the sum of elections falls in a range of either minimal, mild, moderate, or severe anxiety. It asks the participants how much they've been bothered in the past month by the fear of the worst happening, how often they were nervous, unsteady, scared, and feared losing control. As one would suspect, compared to women without PMS, the PMS group had higher anxiety scores. 

The researchers, then, used the Beck Depression Inventory to measure the participant's levels of depression. It also is a 21 question, multiple-choice, self-report inventory that gives a value between 0 and 3 for each question and when all the values are added up, the participant’s total falls in a range of either minimal, mild, moderate, severe, or extreme depression.

It's questions included how sad, discouraged, satisfied, disappointed, and tired they’ve felt. Also assessed, was their appetite, how much weight they’ve lost, how attractive they felt, and how much they cried. This test showed the PMS group had higher depression scores than the non-PMS group.

For stress analysis, study participants completed a Visual Analog Scale for stress. Here, the women specified their level of agreement to statements by indicating a position along a line between two end-points. The test revealed an abnormal stress sensitivity amongst the PMS group. Lastly, an fMRI was given to all the women. 

It also showed the PMS group had abnormal neural connectivity in 5 areas of their brains. The middle frontal gyrus, a processor of language and attention; the parahippocampal gyrus, a processor of memory; the medial temporal gyri, a processor of memory, language, visual perception, and sensory integration; the superior temporal gyri, a processor of sound; and the precentral gyrus, a processor of voluntary motor movement.

The PMS group displayed a higher level of neural activity denoted by the yellow color in the images.

These results suggest that like the PTSD patients, the PMS females had relatively more sensitive brain activation to the threatening stimuli, and this activation still existed even when they were in a resting state not performing tasks. 

All of the above-named areas are in the brain's Default Mode Network (DMN). The DMN is a large-scale brain network of interacting brain regions. The abnormal pattern within the DMN relates to their blunted stress perception, higher anxiety, and depression. Similarly, researchers found abnormal patterns within the DMN of people with ADHD, Schizophrenia, Autism, and Alzheimers disease.