Motivation and reward processing across sex/gender and the menstrual cycle: a biopsychosocial perspective.

BACKGROUND

Females undergo hormonal fluctuations throughout every menstrual cycle and numerously report corresponding symptoms of negative mood or decreased motivation, indicating an increased risk for affective disorders associated with altered motivational behaviour. Understanding whether sex hormones modulate sex/gender-specific behavioural variability in motivation could inform personalised interventions.

METHODS

To assess whether steroid hormone fluctuations and menstrual cycle phase modulate sex/gender-specific motivation, we examined 48 naturally cycling cisgender females and 46 cisgender males, aged 18-34, who performed a physical effort task while fasted (part 1, T0) and across four weeks (part 2, T1-T4). We obtained objective (invigoration and effort maintenance) and subjective (wanting and exertion) measures of motivation in response to food and monetary rewards. Menstrual cycle phases were determined based on cycle-day counting methods alongside plasma levels of estradiol, progesterone, and testosterone. We tested whether females show higher effort maintenance, males exhibit greater reward sensitivity, and explored whether motivational behaviour differs by sex/gender, cycle phase and hormonal variation.

RESULTS

Cross-sectionally, we replicated sex/gender specific reward sensitivity and valuation: Females showed more sustained effort, especially for small rewards, while males displayed more opportunistic approaches seeking monetary rewards. Longitudinally, motivation decreased during periovulatory and luteal phases, whereas levels of endogenous hormones explained little variance in instrumental effort beyond task incentives and sex/gender associations.

CONCLUSIONS

Motivational behaviour in effort-based decision-making is more related to dynamic sex/gender-related factors and menstrual cycle phases overall than to short-term steroid hormone fluctuations. Our findings emphasise the importance of integrating biological, psychosocial, and physiological factors when investigating motivation. Our research has potential implications for personalised interventions and treatment of motivational deficits.