During the menstrual cycle, when progesterone levels are higher, patterns of brain activity emerge that make it more difficult to distinguish between less and more emotionally demanding situations. According to a study led by Professor Macià Buades, from the Faculty of Psychology and the Institute of Neuroscience (UBneuro) of the University of Barcelona, published in the journal
Psychological Medicine (Cambridge University Press), these changes are also associated with a lower mood, which affects women’s emotional well-being.
The study presents a new and precise perspective on the hormonal modulation of mood in young, healthy women. The findings will enable more personalized approaches to assessing and treating hormone-related mood disorders, such as premenstrual dysphoria (severe mood swings before menstruation).
Unravelling the relationship between hormones and emotional well-being
Some women may be more sensitive to progesterone than others, perhaps because their brains have more progesterone receptors. However, the neural mechanisms linking hormonal load and emotional regulation remain poorly understood.
The study explores how the natural levels of the ovarian hormones estradiol and progesterone influence the parts of the brain involved in emotion regulation, and whether this could help explain differences in mood.
The study involved 116 women with natural menstrual cycles (not using hormonal contraceptives). The team applied neuroimaging techniques (magnetic resonance imaging) to study emotional facial expressions, multivoxel decoding techniques and analyses of hormones present in saliva.
When progesterone levels are higher, brain scans reveal a poorer distinction between less and more emotionally-demanding situations. Specifically, the patterns in brain region known as the lateral frontal pole are more similar to one another, suggesting that the brain is less able to differentiate emotional situations in real life. By contrast, when participants showed a clearer distinction between easy and difficult emotional situations, they tended to report a better mood during the previous week.
“The study suggests that if the brain is able to distinguish different emotional situations more clearly, this may help regulate emotions in everyday life,” says Professor Buades, from the UB’s Department of Clinical Psychology and Psychobiology.
“Although we cannot establish cause and effect from a single measure, it is exciting to find information about progesterone that we were previously unaware of,” says the expert.
Does estradiol also affect mood?
Surprisingly, the study found no equivalent effect for estradiol, which is usually associated with an improved mood and is often used to treat menopausal symptoms.
Rosamunde Hendricks, co-author of the study and researcher at the Universitat Autònoma de Barcelona (UAB), notes: “We did not observe an effect comparable to that of progesterone for estradiol, but this may be because estradiol is more difficult to measure accurately in saliva. Therefore, we cannot rule out the possibility that estradiol affects the brain. Rather, it may be that the measurement tools used in this study were unable to detect its effects reliably.”
Traditionally, it has always been thought that hormonal influences on emotional balance are primarily a female phenomenon, a completely mistaken view. Future studies will need to determine whether this link between hormones and emotion regulation observed in women also exists in men. A better understanding of all these mechanisms could help explain the conditions under which hormonal fluctuations are associated with mood changes.
The study was funded by the 2022 Young Investigator Grant given to Macià Buades-Rotger by the Brain & Behavior Research Foundation.