Moniek Hutschemaekers

76 Chapter 4 terone group showed a more reactive fear pattern (higher SUDs) with a steeper decline at the end of the session (See Figure Chapter 4 – Appendix 3). The post-hoc observation that testosterone administration had resulted in steeper fear reductions in participants with high baseline testosterone (session 1) was again made in the second, non-enhanced session, with fear levels showing a similar time(quadratic) x group x baseline-T interaction: Estimate = 1.53(.74), F(1,47) = 4.22, p = .045. In the placebo group, session-2 fear levels followed the same quadratic pattern regardless of baseline testosterone: Estimate = .77(.82), F(1,23) = .94, p = .357. In the testosterone group they showed higher peaks followed by stronger reductions for participants with high baseline testosterone, whereas for those with low baseline testosterone peak fear levels flattened: Estimate = -2.29(1.27), F(1,23) = 3.26, p = .084 (Figure 4.2B). Post-hoc exploration of Heart Rate in session 1 and 23 Our results so far suggest that testosterone may have acute impact on exposure mechanisms, boosting a steeper fear-decline in individuals with high baseline testosterone levels in session 1, which could be relevant for the subsequent transfer to session 2. To deepen our understanding of potential mechanisms affected during session 1, we posthoc explored whether psychophysiological reactivity (HR) mimics the acute effects of testosterone administration on fear levels. HR patterns largely mimicked those of the subjective fear patterns in session 1: There was a non-significant trend towards a time(- linear) x group x baseline-T interaction: Estimate =.80(.42), F(1,44) = 3.64, p = .063. In the placebo group HR decline followed the same slope regardless of baseline testosterone: Estimate = .04(.03), F(1,23) = .056, p = .461, while in the testosterone group HR reduced more for the participants with higher baseline testosterone levels: Estimate = -.12(.06), F(1,21) = 3.89, p = .061. These acute psychophysiological effects did not transfer to the non-enhanced transfer session, indicating that they may support the acute fear reactivity, but that it is the subjective fear pattern that is longer term affected (for full analyses see Chapter 4 – Appendix 1 and Appendix 4 for a Figure). 3 We initially modeled linear, quadratic, and cubic time terms in all HR analyses but dropped the cubic term as it did not improve the model fit.

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