Sex differences in interoception and mental health: an investigation across the menstrual cycle

Many common mental health conditions (e.g. anxiety and depression) are more common in women than men and when women experience mental illness it often presents differently to men. However, what underlies sex differences in mental illness is unclear. Recent research suggests that the ability to perceive the internal state of your body (e.g. feeling your heartbeat; 'interoception') might be important for mental health and key abilities (e.g. emotion processing). Importantly, sex differences in interoception are well documented; compared to men, women are less accurate at perceiving interoceptive signals and yet report more attention to interoceptive signals. Given known links between interoception and mental health, questions remain regarding the extent to which sex differences in interoception relate to sex differences in mental health and why men and women differ with respect to interoception. In women, periods of physical and hormonal change (e.g. the menstrual cycle, pregnancy, menopause) are often associated with changes in mood and mental health. However, whether physical and hormonal change (e.g. during the menstrual cycle) disrupts interoception is not yet known. This project will examine the contribution of interoception to mental health and mood across the menstrual cycle and examine whether interoceptive training improves mental health and mood in both men and women. This research will further our understanding of sex differences in mental illness, and may ultimately help to identify and treat mental illness better when it occurs.

This project investigates whether 1) sex differences in interoception relate to sex differences in common mental disorders (CMDs) and mood 2) sex differences in interoception result from the increased amount of physical and hormonal change females experience and 3) interoceptive training improves CMDs and mood similarly in both sexes. Sex differences in interoception and CMDs are well documented. Compared to males, females exhibit poorer interoceptive accuracy, increased interoceptive attention and are more likely to experience CMDs such as anxiety and depression. Given known links between interoception and CMDs, questions remain regarding the extent to which sex differences in interoception relate to sex differences in CMDs, the mechanism(s) underlying sex differences and the extent to which interoceptive training results in CMD improvements in both sexes.

This project will test the hypotheses that 1) sex differences in interoception relate to sex differences in CMDs and mood, and 2) sex differences in interoception result from the increased amount of physical and hormonal change females experience. This will be achieved by longitudinally assessing interoception, CMDs and mood across the menstrual cycle (or a comparable period) in three groups: males and females who are, and are not, using hormonal contraception. Cardiac interoceptive accuracy, interoceptive attention, mood, CMDs and menstrual cycle phase will be assessed remotely via a smartphone application. Lab-based tasks of respiratory and arousal interoceptive accuracy and emotion regulation will be completed by a subset of participants. Finally, a training study will be used to determine whether interoceptive training improves CMDs and mood similarly in both sexes. Findings will inform our understanding of sex differences in CMDs and mood, the temporal and mechanistic relationship between interoception, CMDs and mood, and inform personalised timing and selection of clinical interventions.