What is there to know about the effects of progestins on the human brain and cognition?

The link between daily affective complexity and anxiety is altered by oral contraceptive use

Affective complexity - the unique ways in which individuals' emotions covary and differentiate - is an important aspect of internalizing problems. For instance, daily affective complexity has been linked to anxiety increases in women and to decreases in men. The mechanisms underlying this gender difference have not been widely investigated, but a role for ovarian hormones is likely. Research on oral contraceptives (OCs) provides promising insights into such mechanisms, as OCs suppress endogenous ovarian hormone production and vary in exogenous hormone formulations. Thus, the goal of this study was to examine links between daily affective complexity and internalizing problems in OC users (n = 84), focusing on dimensionally-assessed anxiety, and to investigate whether the links varied by pill formulation. Affective complexity was operationalized as number of factors for each person, as estimated by p-technique (i.e., person-specific factor analysis) of 75-day intensive longitudinal data. There was not a relation between affective complexity and anxiety in OC users, and this did not depend on OC pill formulation (i.e., estrogenic, progestational, or androgenic activities). Thus, OC use may blunt the relation between affective complexity and anxiety, as OC users had a relation in between the established positive relation for naturally cycling women and the inverse for men (despite a similar range of factors). Findings are consistent with a growing literature showing that OC use modulates stress and anxiety-linked processes, and suggest that gendered mechanisms underlying the relation between affective complexity and anxiety may be suppressed along with ovarian hormones in OC users.

The levonorgestrel-releasing intrauterine device is related to early emotional reactivity: An ERP study

Despite the evidence of altered emotion processing in oral contraceptive (OC) users, the impact of hormonal intrauterine devices (IUD) on emotional processing remains unexplored. Our study aimed to investigate how behavioural performance and event-related potentials (ERPs) linked with emotion reactivity and its regulation are associated with hormonal profiles of women using different types of hormonal contraception and naturally cycling women. Women using OCs (n = 25), hormonal IUDs (n = 33), and naturally cycling women in their early follicular (NCF, n = 33) or mid-luteal (NCL, n = 28) phase of the menstrual cycle were instructed to view emotional pictures (neutral, low and high negativity) and use cognitive reappraisal to up- or down-regulate negative emotions, while their electroencephalogram was recorded. Participants rated perceived negativity after each picture and their emotional arousal throughout the task. Saliva samples were collected to assess levels of 17β-estradiol, progesterone, and testosterone. As expected, emotional arousal increased throughout the task and correlated positively with perceived negativity. Perceived negativity and the amplitudes of the middle (N2/P3) and later (LPP) latency ERP components increased with increasing stimuli negativity. Emotion regulation modulated perceived negativity and the amplitudes of very late ERP components (parietal and frontal LPP). Moreover, IUD-users showed a higher negative amplitude of the frontal N2 in comparison to all three other groups, with the most consistent differences during up-regulation. Finally, testosterone correlated positively with the N2 peak in IUD-users and NCL women. Overall, our findings suggest that IUD-use and testosterone might be related to altered preconscious processing during the emotion regulation task requiring attention to the stimulus. The study underscores the need for additional research into how different hormonal contraceptives are linked to socio-emotional functioning.

Levonorgestrel maintains goal-directed behavior in habit-trained intact female rats

Hormonal contraceptives are utilized by millions of women worldwide. However, it remains unclear if these powerful endocrine modulators may alter cognitive function. Habit formation involves the progression of instrumental learning as it goes from being a conscious goal-directed process to a cue-driven automatic habitual motor response. Dysregulated goal and/or habit is implicated in numerous psychopathologies, underscoring the relevance of examining the effect of hormonal contraceptives on goal-directed and habitual behavior. This study examined the effect of levonorgestrel (LNG), a widely used progestin-type contraceptive, on the development of habit in intact female rats. Rats were implanted with subcutaneous capsules that slowly released LNG over the course of the experiment or cholesterol-filled capsules. All female rats underwent operant training followed by reward devaluation to test for habit. One group of females was trained at a level that is sub-threshold to habit, while another group of females was trained to a level well over the habit threshold observed in intact females. The results reveal that all sub-threshold trained rats remained goal-directed irrespective of LGN treatment, suggesting LNG is not advancing habit formation in female rats at this level of reinforcement. However, in rats that were overtrained well above the threshold, cholesterol females showed habitual behavior, thus replicating a portion of our original studies. In contrast, LNG-treated habit-trained rats remained goal-directed, indicating that LNG impedes the development and/or expression of habit following this level of supra-threshold to habit training. Thus, LNG may offset habit formation by sustaining attentional or motivational processes during learning in intact female rats. These results may be clinically relevant to women using this type of hormonal contraceptive as well as in other progestin-based hormone therapies.

The role of sex hormones, oral contraceptive use, and its parameters on visuospatial abilities, verbal fluency, and verbal memory

Sex hormones can cross the blood-brain barrier and access brain regions underlying higher-order cognition. Containing synthetic sex hormones, oral contraceptives (OC) have been found to modulate visuospatial and verbal abilities, though inconsistencies have been found in the literature. Among possible explanations, certain OC use parameters (progestin androgenicity, synthetic hormone levels, duration of use) have not received consistent consideration. Thus, the objectives were to (1) examine group differences between men, combined OC users, and naturally cycling women (NC women; not using OC) in visuospatial abilities, verbal fluency, and verbal memory and (2) investigate the contribution of endogenous and exogenous sex hormones on these effects. We also aimed to (3) identify OC use parameters relevant to cognitive outcomes. In total, 70 combined OC users, 53 early follicular (EF) women, 43 pre-ovulatory (PO) women, and 47 men underwent cognitive tests. Performance was compared based on hormonal milieus (OC, EF, PO, men) and OC users' contraceptive androgenicity (anti, low, high). Correlations between performance, hormone levels and OC use duration were also conducted. OC use dampened the sex difference that typically favors men in 3D visuospatial abilities, whereas its duration of use positively predicted verbal fluency. Androgenicity and hormone levels did not predict performance in any task. These results highlight the importance of considering OC use duration. Results also did not support a role for androgenicity in cognition. Importantly, combined OC use (including prolonged use) does not impair visuospatial, verbal, and memory functions in a healthy young sample.

Women in their mid-follicular phase outcompete hormonal contraceptive users, an effect partially explained by relatively greater progesterone and cortisol reactivity to competition

Early evidence suggests that hormonal contraceptive (HC) use alters psychological functioning and competitive behavior. Yet, there is limited data on endocrine models for explaining how HC use affects these outcomes. In this pre-registered and open-data study, we test if HC users and naturally cycling (NC) females in their low (mid-follicular) and high (mid-luteal) progesterone phase differ in competitive persistence and whether progesterone and cortisol reactivity mediate of this effect. HC users (N = 73) in the active hormone-exposure phase and NC participants in the mid-follicular (N = 69) or mid-luteal (N = 72) phase completed two behavioral measures of competitive persistence, holding up a weight for time followed by attempting to solve an unsolvable anagram. Participants also completed measures of handgrip strength and self-reported competitiveness as well as gave saliva samples before and after the tasks for hormone assay. Results showed that NC-follicular group had greater competitive persistence in the weight-holding task compared to both NC-luteal (d = 0.38) and HC use (d = 0.43) groups independent of physical strength and self-reported competitiveness covariates. Although anagram task performance showed similar trends for group differences, analyses for this task were inconclusive. Baseline progesterone did not mediate the effect of cycle phase group on competitive persistence. HC users showed relatively blunted cortisol and progesterone reactivity, and this effect partially mediated the difference in competitive persistence between HC users and the NC-follicular group. In sum, results suggest that HC use could downregulate competitive behavior at least partly by dampening cortisol-progesterone reactivity. These findings offer a new endocrine model for understanding HC use and cycle phase effects on motivational and energetic outcomes required for optimal performance in competitive contexts.

Weak associations between personality and contraceptive choice

Prospective randomized controlled trials on hormonal contraceptive (HC) effects on the brain are rare due to a number of methodological challenges. Thus, much of the evidence on HC effects on the brain comes from cross-sectional studies comparing HC-users to non-users. In interpreting these findings, it is of importance to be aware of potential confounds associated with women's contraceptive choices. Previous studies have discussed age, education, social status, sexual orientation, relationship status, and tolerability of HC. Given the current trend toward a reduction in HC use and increased skepticism toward HC it seems relevant to also identify variables associated with women's attitudes toward HC and whether they may represent confounds for neuroscientific studies. In the present study, we investigated whether women's personality characteristics were associated with their choice to use or not use HC in the present, past and future and the type of HC chosen. 1,391 females aged 18-45 years participated in an online survey including the HEXACO-60 personality questionnaire, as well as two different measures of gender role, and provided information about their current and previous contraceptive status, as well as experiences with and attitudes toward contraceptive use. We compared (i) current, previous and never-users of HC, (ii) prospective users of HC to women who opposed future HC use, and (iii) current users of IUDs to current users of oral contraceptives. Results revealed that associations between personality and the decision to use or not use HC were negligible, while differences in personality were observed corresponding to contraceptive type. Current users of IUDs showed higher agreeableness and extraversion compared to current users of oral contraceptives. The results suggest that personality is more strongly associated to the choice of contraceptive type rather than the choice between hormonal and non-hormonal options.

Hormone-based models for comparing menstrual cycle and hormonal contraceptive effects on human resting-state functional connectivity

Oral contraceptives (OCs) are widely used yet understudied given their potential for public health consequences. Emerging investigations scaling from single-subject, dense-sampling neuroimaging studies to population-level metrics have linked OCs to altered brain structure and function. Modeling the hypogonadal, hypergonadal, or mixed state effects of OCs in terms of their impact on hormone action in the brain is a valuable approach to synthesizing results across neuroimaging studies and comparing OC effects to companion findings from research on menstrual cycle phase effects on brain anatomy and function. Resting-state functional connectivity studies provide a powerful tool to evaluate the role of OCs on the intrinsic network connectivity that underlies multiple behavioral domains. The preponderance (but not consensus) of the current literature indicates that (1) as the menstrual cycle proceeds from a low to high progesterone state, prefrontal connectivity increases and parietal connectivity decreases; (2) OCs tend to mimic this connectivity pattern; therefore (3) OCs may produce a hyperprogestogenic state in the brain, in spite of overall reductions in endogenous steroid hormone levels. Alternative models are also considered.