Using electrodermal activity to estimate fear learning differences in anxiety: A multiverse analysis.

Meta-analyses indicate differences in Pavlovian fear responses between anxious and non-anxious individuals using electrodermal activity (EDA). Recent research, however, has cast doubt on whether these effects are robust to different analytic choices. Using the multiverse approach conceived by Steegen et al. (2016), we surveyed analytic choices typically implemented in clinical fear conditioning research by conducting 1240 analyses reflecting different choice permutations. Only 1.45% of our analyses produced theoretically congruent statistically significant effects, and the strength and direction of the estimated effects varied substantially across EDA processing methods. We conclude that EDA-estimated fear learning differences are vulnerable to researcher degrees of freedom and make recommendations regarding which analytical choices should be approached with a high degree of caution.

Sex differences in intrusive memories following trauma.

BACKGROUND: A key mechanism thought to underlie Posttraumatic Stress Disorder (PTSD) is enhanced emotional memory consolidation. Recent evidence in healthy controls revealed that women have greater negative memory consolidation following stress relative to men. This study examined emotional memory consolidation in women and men with PTSD, and in trauma-exposed and non-trauma controls to test the hypothesis that emotionally negative memory consolidation would be greater in women with PTSD. METHOD: One hundred and forty-seven men and women (47 with PTSD, 49 trauma-exposed controls, and 51 non-trauma controls) completed an emotional memory task where they looked at negative, neutral and positive images from the International Affective Picture System (IAPS). Delayed recall and an intrusive memory diary were completed two days later. RESULTS: Women displayed greater recall, and reported more negative intrusive memories than men. A gender x group interaction effect showed that both women with PTSD and trauma-exposed women reported more intrusive memories than women without trauma exposure or men. CONCLUSION: This study provided preliminary evidence of sex differences in intrusive memories in those with PTSD as well as those with a history of trauma exposure. Future research should include measures of sex hormones to further examine sex differences on memory consolidation in the context of trauma exposure and PTSD.

Negative appraisals and fear extinction are independently related to PTSD symptoms.

BACKGROUND: Considerable research has revealed impaired fear extinction to be a significant predictor of PTSD. Fear extinction is also considered the primary mechanism of exposure therapy, and a critical factor in PTSD recovery. The cognitive theory of PTSD proposes that symptoms persist due to excessive negative appraisals about the trauma and its sequelae. Research has not yet examined the relationship between fear extinction and negative appraisals in PTSD. METHODS: A cross-sectional sample of participants with PTSD (n =21), and trauma-exposed controls (n =33) underwent a standardized differential fear conditioning and extinction paradigm, with skin conductance response (SCR) amplitude serving as the index of conditioned responses. The Posttraumatic Cognitions Inventory (PTCI) was used to index catastrophic negative appraisals. RESULTS: Participants with PTSD demonstrated a slower decrease in overall SCR responses during extinction and greater negative appraisals compared to the group. A moderation analysis revealed that both negative trauma-relevant appraisals and fear extinction learning were independently associated with PTSD symptoms, but there was no moderation interaction. LIMITATIONS: The current study was limited by a modest sample size, leading to the inclusion of participants with subclinical PTSD symptoms. Further, the current study only assessed fear extinction learning; including a second day extinction recall task may show alternative effects. CONCLUSIONS: These findings indicate that negative appraisals and fear extinction did not interact, but had independent relationships with PTSD symptoms. Here we show for the first time in an experimental framework that negative appraisals and fear extinction play separate roles in PTSD symptoms.

IMPAIRED FEAR EXTINCTION ASSOCIATED WITH PTSD INCREASES WITH HOURS-SINCE-WAKING.

BACKGROUND: Prior research has demonstrated that time-of-day may play an important role in the extinction of conditioned fear, with extinction better learned earlier in the day rather than later. Impaired fear extinction memory is widely considered a key mechanism of posttraumatic stress disorder (PTSD). The relationship between fear extinction and PTSD symptoms may be moderated by hours-since-waking. METHOD: In the present experiment, we examined whether hours-since-waking would moderate fear extinction learning ability in a clinical PTSD sample (n = 15), compared to trauma-exposed (n = 33) and nonexposed controls (n = 22). Participants completed a standardized differential fear conditioning and extinction paradigm, providing skin conductance response measures to quantify conditioned responding. RESULTS: Mixed-model analysis of variance revealed a PTSD-specific impairment in extinction learning ability in the late extinction phase. A moderation analysis showed that hours-since-waking was a significant moderator of the relationship between impaired late extinction and PTSD symptoms. Specifically, we found that participants with higher PTSD symptoms demonstrated poorer fear extinction learning ability as they were awake for longer. CONCLUSIONS: The results of the current study add to a growing literature indicating deficits in fear extinction learning in PTSD samples, compared to trauma-exposed and nonexposed controls. These results support previous findings that fear extinction is impaired later in the day, and extends this to a clinical sample, suggesting that exposure-therapy may be optimized by scheduling sessions in the morning.

Interaction of noradrenaline and cortisol predicts negative intrusive memories in posttraumatic stress disorder.

Recent evidence suggests that an interaction of noradrenaline (NE) and cortisol (CORT) during encoding leads to greater consolidation of emotional memories. Convergent models of posttraumatic stress disorder (PTSD) suggest the release of CORT and NE lead to greater intrusive memories in PTSD. This study examined the effect of NE and CORT during encoding on recall and intrusive memories in PTSD. Fifty-eight participants (18 participants with PTSD, 20 trauma-exposed controls, and 20 non-trauma exposed controls) provided saliva samples of NE (indexed by salivary alpha amylase; sAA) and CORT at (a) baseline and (b) after viewing negative emotional stimuli. Delayed memory recall and number of intrusive memories of negative, neutral and positive stimuli were recorded two days after this initial testing session. The PTSD group had greater NE levels to negative stimuli and reported greater numbers of intrusive memories of negative stimuli than controls. Regression analyses revealed that the interaction of CORT and NE significantly predicted negative intrusive memories in the PTSD group. The trauma-exposed group reported significantly greater recall of negative images compared to controls, but did not differ significantly from the PTSD group. The PTSD group reported greater levels of suppression of negative images during encoding compared to the other groups. Our results confirm that the interaction of NE and CORT significantly predicts greater negative intrusive memories, but this occurs specifically in the PTSD group. This suggests that a level of heightened arousal is required for the relationship between stress hormones and emotional memory to manifest in PTSD.