When the brain changes monthly: Neuropsychology of PMS

As a woman, you know the drill all too well. One minute you're feeling on top of the world, the next you're a sobbing mess over a spilled latte. Premenstrual syndrome (PMS) is a complex condition that affects many women during the luteal phase of their menstrual cycle, the time between ovulation and the start of menstruation. While the physical symptoms of PMS, such as bloating, cramps, and breast tenderness, are well-known, the neuropsychological aspects of this cyclical disorder are often overlooked. Hello and welcome back, Thinkers! In this blog post, we'll dive into the fascinating world of the "PMS brain" and explore how hormonal fluctuations can impact everything from your emotional regulation to your cognitive performance. 

Emerging research has revealed that the structure of the brain undergoes subtle yet significant changes in sync with hormonal fluctuations throughout the menstrual cycle. A study published in the preprint database bioRxiv found that the brain volume and composition of gray and white matter in 30 women varied across the different phases of their cycles. Specifically, the researchers observed increases in gray matter volume in regions like the precuneus, inferior temporal cortex, and inferior frontal cortex during the luteal phase, when PMS symptoms typically peak. Conversely, they found decreased gray matter in the anterior cingulate cortex (ACC) - a key hub for emotional regulation and cognitive control. These structural changes correlated with the severity of self-reported PMS symptoms, suggesting a direct link between brain morphology and the psychological manifestations of PMS.

Beyond structural differences, PMS has also been associated with abnormal patterns of brain activity and connectivity. A study using resting-state fMRI found that women with PMS exhibited increased regional homogeneity (a measure of local synchronization of brain signals) in regions like the precuneus, inferior temporal cortex, and middle frontal cortex, along with decreased homogeneity in the ACC . This dysregulation of spontaneous brain activity may underlie the emotional lability, irritability, and difficulty with cognitive control that are hallmarks of PMS.

Interestingly, the severity of PMS symptoms, as measured by the Daily Record of Severity of Problems (DRSP) questionnaire, was positively correlated with activity in the middle frontal cortex but negatively correlated with activity in the ACC . This suggests that the ACC, which is involved in higher-order cognitive functions and emotional regulation, may be less able to exert top-down control during the luteal phase in women with PMS.

The cyclic nature of PMS is closely tied to the fluctuations in ovarian hormones, such as estrogen and progesterone, that occur throughout the menstrual cycle. These hormones have been shown to influence brain structure and function, with estrogen promoting the growth of new neural connections and progesterone having anti-anxiety and anti-depressive effects. Stress is another key factor that can exacerbate PMS symptoms. Chronic stress has been linked to abnormalities in the hippocampus, a brain region involved in memory and emotion regulation, as well as changes in neurotransmitter levels like cortisol, dopamine, and norepinephrine. These stress-induced brain changes may further contribute to the emotional and cognitive difficulties experienced by women with PMS.

The growing body of research on the neuropsychology of PMS highlights the complex interplay between hormonal, structural, and functional brain changes that underlie this cyclical disorder. By understanding the neural mechanisms involved, we can better develop targeted interventions, whether pharmacological, psychological, or lifestyle-based, to help women manage their PMS symptoms. Moreover, the findings from these studies underscore the importance of considering sex-specific factors in neuroscience and psychology research. As Viktoriya Babenko, one of the authors of the bioRxiv study, pointed out, "Most of what we know about the human body is from studies that were carried out primarily on the male body". By focusing more on the unique experiences and biology of people who menstruate, we can gain a more comprehensive understanding of the human brain and its dynamic changes over time.

In conclusion, the neuropsychology of PMS is a fascinating and rapidly evolving field that sheds light on the intricate relationship between the brain, hormones, and the menstrual cycle. As we continue to unravel the complex neural mechanisms underlying this condition, we can work towards improving the quality of life for the millions of women who experience the monthly rollercoaster of PMS.