Does increased brain reward sensitivity protect mood during the premenstrual phase?

The menstrual cycle involves hormonal fluctuations that can impact mental health. During the premenstrual phase, many people who menstruate experience the onset or exacerbation of low mood, anxiety, irritability, anhedonia, and somatic symptoms. We hypothesised that estradiol’s influence on motivational decision-making may underpin worsening mental health during the premenstrual phase. To test this, we tracked effort-based decision-making at two key points in the menstrual cycle using a well-validated physical effort-expenditure task and computational model. Two hundred naturally cycling participants from the general population completed the task and psychiatric measures in a counterbalanced order during their menstrual cycle’s periovulatory phase (marked by high estradiol and low progesterone) and perimenstrual phase (marked by low estradiol and low progesterone). As expected, mental health symptoms (including depression, anxiety, and anhedonia) worsened during the perimenstrual phase. Computational modelling revealed that the perimenstrual phase was characterised by increased reward sensitivity and decreased acceptance bias during effort-based decision-making. Importantly, those individuals who exhibited larger perimenstrual increases in reward sensitivity showed smaller increases in depression symptoms. These findings suggest that perimenstrual shifts in reward sensitivity in the general population represent a neurocognitive response to declining estradiol that may help buffer against low mood.

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