DOES THE PILL IMPEDE UNLEARNING FEAR? The impact of oral contraception use on fear extinction in an online conditioning

Abstract

Research on psychological effects of oral contraception (OC) use has suggested negative effects. Specifically, OC use has been linked to fear extinction deficits. This study examined the effect of OC use and OC pill phase on fear extinction. 251 participants completed an online experiment including a fear conditioning task and multiple questionnaires. In the first phase of the conditioning task, an image was conditioned to evoke fear in participants. In the second phase participants received extinction training to ‘unlearn’ previously acquired fear. Fearfulness ratings to the conditioned stimulus over the experiment were analysed and compared between groups of OC users and natural cyclers (NCs) and between OC users in different pill phases. Firstly data-driven latent growth modelling (LCGA) identified three distinct fear conditioning trajectories in participants, indicating their success of extinguishing fear. Contrary to the expectations, OC users and OC users in an active pill phase were not overrepresented in the class of poor extinguishers (N= 114). Also, no effects in the classes of normal conditioners (N = 77) and low fearful conditioners (N = 60) were found. Secondly, final fear scores of participants after extinction training were compared. OC users and OC users in an active pill phase did not show more fear compared to NCs and OC users in a pill-free week. Results of this study do not indicate disadvantageous effects of OC use and do not show an acute effect of hormones from the pill. Both hypotheses were rejected, but more research is needed to definitively rule out any unshown effect. Samples were small, resulting in low meaningful comparison of class subgroups containing under 10 OC users. Future studies should contain more OC users and more NCs. A distinction of NCs in different menstrual phases is recommendable for disentangling effects of endogenous and exogenous hormones. The approach presented in this study can be used in future research.