Birth control pills linked to changes in depressive mood processing

A study of young, healthy women found that they tend to display stronger depression-like patterns of cognitive processing when actively taking oral contraceptives. This effect was particularly pronounced among women with generally higher levels of depressive symptoms. The findings were published in the journal Frontiers in Psychology.

Oral contraceptives, commonly known as birth control pills, are medications taken orally to prevent pregnancy. They typically contain synthetic hormones—either a combination of estrogen and progestin (combined oral contraceptives) or progestin alone (progestin-only pills). These hormones work by preventing ovulation (the release of an egg from the ovary). Additionally, they thicken cervical mucus, making it more difficult for sperm to reach the egg, and alter the uterine lining, reducing the likelihood of implantation should fertilization occur.

Oral contraceptives are highly effective when taken consistently at the same time each day. Beyond preventing pregnancy, they can regulate menstrual cycles, reduce menstrual cramps, and treat acne. However, they may carry risks or side effects, such as an increased risk of blood clots or hormonal changes. Some evidence also suggests that increased depressive symptoms may occur in women using combined oral contraceptives.

Study author Elizabeth Hampson and her colleagues sought to explore whether oral contraceptives contribute to a more depressive mindset in their users. Combined oral contraceptives are typically taken daily for 21 or 24 days, followed by an inactive phase lasting several days when users either take placebo pills (included in the contraceptive package) or abstain from taking pills altogether. During the inactive phase, synthetic hormones are not used. The researchers hypothesized that if oral contraceptives induce depressive symptoms, depression scores would be higher during the active hormone phase compared to the inactive phase.

The study included 53 young, healthy women aged 18–26, who were either university students or administrative staff. All participants had been using standard combined oral contraceptives for at least three months and had no chronic health conditions or other prescription medications. Participants were compensated $25 to cover travel costs.

Participants completed a set of tests at two time points: during the second or third week of the active phase of their contraceptive cycle (when they were actively taking hormones) and during the inactive phase (when no hormones were taken).

The participants completed a mood assessment using the Profile of Mood States (POMS), which evaluates six dimensions: Anxiety, Depression, Anger/Irritability, Vigor, Fatigue, and Confusion. They also completed the Facial Emotion Identification Task, which involved identifying emotional expressions from a set of 96 test faces. Previous research has shown that negative faces (e.g., sad or angry expressions) more readily capture the attention of individuals with depression. The authors anticipated similar findings.

In addition, participants completed the Affect Misattribution Procedure and the Emotional Stroop Task. The Affect Misattribution Procedure involved presenting unfamiliar Chinese characters preceded by images of flowers or insects. These images were intended to influence participants’ evaluation of the pleasantness of the characters. The authors examined whether this effect varied between the active and inactive phases of contraceptive use. The Emotional Stroop Task assessed depressive-like processing of visual stimuli by measuring response times to incongruent and congruent emotional face-word pairings.

Self-reported mood profiles indicated that negative moods, including depression, were higher during the inactive phase of the oral contraceptive cycle. Notably, 29% of participants exhibited elevated depression scores during both testing sessions. In this subgroup, depression levels were comparable to those observed in outpatients diagnosed with anxiety or mild to moderate depression.

In contrast, implicit measures of affect (such as the Affect Misattribution Procedure and Emotional Stroop Task) revealed a more depressive-like pattern of performance during the active hormone intake phase. This effect was especially pronounced in participants who generally reported higher levels of depressive symptoms.

“The present findings reinforce the possibility of depressive mood effects associated with OC [oral contraceptives] usage, and highlight the utility of including implicit measures, but also illustrate the complexity of mood assessment in OC users,” the, study authors concluded.

The study contributes to the scientific understanding of side-effects of oral contraceptives. However, it was conducted on a small sample of young, healthy women and highlighted a discrepancy between self-reported mood and cognitive processing indicators. Studies on other demographic groups and using different methodologies may yield different results.

The paper, “Current oral contraceptive use affects explicit and implicit measures of depression in women,” was authored by Elizabeth Hampson, Sara N. Abrahamson, Taylor N. Breddy, Maisha Iqbal, and Elena R. Wolff.