Patterns in affect and personality states across the menstrual cycle

Area of Science:

• Psychology
• Endocrinology
• Behavioral Science

Background:

• Personality states and affect vary across situations, but underlying biological mechanisms are not fully understood.
• The menstrual cycle and hormonal fluctuations are potential regulators of these state changes.

Purpose of the Study:

• To investigate how personality states and affect change during the menstrual cycle.
• To examine the influence of ovarian hormones and hormonal contraceptive use on these fluctuations.

Main Methods:

• Two large longitudinal studies were conducted: an online diary study (N=757) and a laboratory study with hormone assays (N=257).
• Data collected included daily affect, personality states, and, in Study 2, repeated hormone measurements.

Main Results:

• Study 1 found minimal differences between naturally cycling women and hormonal contraceptive users, except for greater negative affect variability in users.
• Study 2 revealed premenstrual increases in neuroticism and negative affect, and decreases in extraversion and positive affect.
• Higher extraversion and lower neuroticism correlated with conception risk and estradiol-to-progesterone ratio, suggesting fertility-linked adaptive shifts.

Conclusions:

• Hormonal variations across the menstrual cycle, particularly premenstrual phases, are significant biological sources of personality state variation.
• Methodological differences between studies may explain divergent findings.
• Future research should consider these hormonal influences and refine methodologies.