Psychological Medicine: Progesterone Levels Are Linked to How the Brain Processes Emotions

The study included 116 healthy women aged 18–35 who were not using hormonal contraceptives. The researchers measured progesterone and estradiol levels in their saliva and asked the participants to rate their mood over the previous week.

During functional MRI scans, the participants completed a task involving photographs of happy and angry faces. By pressing a button, they could make an image appear closer or farther away. In some trials, the instructions matched typical responses — approaching a friendly face and moving away from an angry one. In other trials, participants were required to do the opposite.

After excluding six participants who made errors too frequently, the researchers analyzed data from 110 women. They used a computational method to distinguish between task conditions based on spatial patterns of brain activity.

Higher progesterone levels were associated with lower classification accuracy in the lateral frontal pole and the striatum. The former region is involved in overriding automatic emotional responses. Less distinguishable signals in this region were also associated with poorer mood over the preceding week.

However, these findings reflect statistical associations rather than evidence that the hormone directly affects mood or self-control. Hormone levels were measured only once, so the study cannot show how an individual woman's responses change throughout her menstrual cycle.

The results point to a possible mechanism linking hormonal status with emotional processing. Repeated measurements in the same participants could help test this hypothesis. The findings do not justify drawing conclusions about women's personalities or emotional resilience.