Flipbook

CHAPTER 8 192 this may cause a shift in the internal context, and cause a return of fear. In chapter 2, removal of the availability of safety behavior after extinction learning may have caused contextual renewal. It remains unclear whether negative occasion setting or contextual renewal explains the finding that safety behavior that minimized the severity of threat prevented extinction learning in chapter 2 (van Uijen, Dalmaijer, et al., 2017). Figure 3. Inhibitory learning is context-dependent (Vervliet et al., 2013). The circle with CX indicates the context in which the inhibitory association was learned. In the extinction context, the inhibitory association is active. Furthermore, it remains unclear why safety behavior that minimized the severity of threat prevented extinction for several participants, yet allowed extinction for other participants in chapter 2 (van Uijen, Dalmaijer, et al., 2017). Although this finding was obtained from a small ( n = 21), and specific (i.e., undergraduate students) sample and should therefore be interpreted with caution, it suggests that safety behaviors that minimize threat severity, but do not prevent the occurrence of threat, may have negative effects on exposure outcomes for some, but not all, individuals. Animal fear conditioning studies found individual differences in extinction (Galatzer-Levy, Bonanno, Bush, & LeDoux, 2013) and avoidance learning (Galatzer- Levy et al., 2014) in rats. These individual differences are analogous to the heterogeneous patterns of change in posttraumatic stress disorder (PTSD) symptoms after trauma in humans (Bonanno, 2004, 2005): after an aversive event, some individuals adapt rapidly and completely, others adapt slowly, and others fail to adapt. Prospective research has shown that impaired extinction learning before trauma predicts later PTSD symptoms (Lommen, Engelhard, Sijbrandij, van den US The role of context after extinction CS CX