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Fear extinction in traumatized civilians with posttraumatic stress disorder: relation to symptom severity.

ABSTRACT: The symptoms of posttraumatic stress disorder (PTSD) can be explained, at least in part, as an inability to inhibit learned fear during conditions of safety. Our group has shown that fear inhibition is impaired in both combat and civilian PTSD populations. On the basis of our earlier findings, we employed an established fear extinction paradigm to further explore fear dysregulation in a civilian traumatized population.Fear-potentiated startle (FPS) was examined in 127 trauma-exposed individuals with and without PTSD. We used a protocol in which conditioned fear was first acquired through the presentation of one colored shape (reinforced conditioned stimulus, [CS+]) that was paired with an aversive air blast to the larynx (unconditioned stimulus) and a different colored shape that was not paired to the air blast (nonreinforced condition stimulus). Fear was extinguished 10 min later through repeated presentations of the CSs without reinforcement.Both groups demonstrated successful fear conditioning on the basis of startle and unconditioned stimulus-expectancy ratings; however, participants with PTSD displayed greater FPS responses to the CS+ and nonreinforced conditioned stimulus compared with the group without PTSD. During fear extinction, the PTSD group showed elevated FPS responses to the previously reinforced CS+ during the early and middle stages of extinction. During the acquisition and extinction phases, PTSD participants with higher levels of reexperiencing symptoms exhibited greater potentiated startle responses to the CS+ compared with PTSD participants with lower reexperiencing symptoms.These results suggest that PTSD is associated with enhanced fear learning and a greater "fear load" to extinguish after conditioned fear is acquired.

SUBMITTER: Norrholm SD

PROVIDER: S-EPMC3052965 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

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Fear extinction in traumatized civilians with posttraumatic stress disorder: relation to symptom severity.

Norrholm Seth D SD Jovanovic Tanja T Olin Ilana W IW Sands Lauren A LA Karapanou India I Bradley Bekh B Ressler Kerry J KJ

Biological psychiatry 20101029 6

<h4>Background</h4>The symptoms of posttraumatic stress disorder (PTSD) can be explained, at least in part, as an inability to inhibit learned fear during conditions of safety. Our group has shown that fear inhibition is impaired in both combat and civilian PTSD populations. On the basis of our earlier findings, we employed an established fear extinction paradigm to further explore fear dysregulation in a civilian traumatized population.<h4>Methods</h4>Fear-potentiated startle (FPS) was examined ...[more]

PMID: 21035787

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Project description:Disrupted sleep is a major feature in numerous clinical disorders and is related to decrements in affective memory processing. The prevalence of sleep disruption in post-traumatic stress disorder (PTSD) is suggested to be a key feature that exacerbates the impaired ability to recall extinction memories during experimental fear conditioning. We hypothesized that an intervention employing blue-wavelength light therapy (BLT) to regulate sleep and stabilize circadian rhythms in patients with PTSD (i.e., via regulated morning exposure) would be associated with PTSD symptom improvement, decreased sleep-related complaints, as well as improved consolidation and retention of extinction memories relative to a fear conditioning/extinction paradigm. Eighty-two individuals with PTSD underwent a well-validated fear conditioning/extinction protocol with subsequent assignment to receive morning BLUE (BLT) or placebo AMBER (ALT) light therapy daily for 30-min over 6-weeks. Participants returned after the intervention for post-treatment extinction recall, comprised of exposure to the previously conditioned stimuli, with the difference in skin conductance response between the "extinguished" and the "never-extinguished" stimuli at follow-up. Participants also viewed previously conditioned stimuli in a novel context during a functional magnetic resonance imaging (fMRI) scan. BLUE light therapy was associated with improvements relative to correlated decreases between PTSD symptoms and sleep-related complaints. Participants receiving BLT also sustained retention of the extinction memory, while those in the placebo amber light treatment group showed impairment, characterized by the restoration of the extinguished fear response after 6-weeks. Participants in the ALT also demonstrated greater reactivity in the left insula when viewing the previously extinguished fear-conditioned stimuli in a novel context. Daily BLUE-wavelength morning light exposure was associated with greater retention of extinction learning in patients with PTSD when compared to ALT, as supported by both autonomic and neurobiological reactivity. We speculate that improved sleep facilitated by a stabilized circadian rhythm, after fear-learning, led to greater consolidation of the fear extinction memory, decreased PTSD symptom presentation, and associated decreases in sleep-related complaints. Prominent exposure treatments for PTSD incorporate principles of fear extinction, and our findings suggest that blue light treatment may facilitate treatment gains by promoting the consolidation of extinction memories via improved sleep.

Project description:BackgroundUp to 50% of individuals with posttraumatic stress disorder (PTSD) endorse problematic alcohol use. Typically, these individuals present with more complex and often more severe PTSD symptoms than those who do not report problematic alcohol use. Emerging literature suggests that heightened symptoms of dissociation are likewise associated with greater PTSD symptom severity. Despite this knowledge, the role of dissociation in the relation between PTSD severity and alcohol-related problems has yet to be examined. Here, we explore the mediating role of dissociative symptomatology on the association between PTSD severity and alcohol-related problems within a PTSD treatment-seeking sample.MethodsStructural equation modeling was used to test the mediating role of dissociative symptomatology between PTSD severity and alcohol-related problems. Participants [N = 334; mean age (SD) = 44.29 (9.77), 50% female] were drawn from a clinical intake battery database for PTSD in-patient treatment services at Homewood Health Care, Guelph, ON, Canada. A subset of battery measures assessing PTSD severity, dissociative symptomatology, and alcohol-related problems were submitted to analysis.ResultsA significant positive association emerged between PTSD severity and alcohol-related problems (β = 0.127, p < 0.05) in the absence of dissociative symptomatology. Critically, however, when added to this model, dissociative symptomatology (six unique facets of dissociation assessed by the Multiscale Dissociation Inventory) mediated the relation between PTSD severity and alcohol-related problems. Specifically, greater PTSD severity was associated with greater dissociative symptomatology (β = 0.566, p < 0.0001), which was in turn associated with greater alcohol-related problems (β = 0.184, p < 0.05).ConclusionsThese results suggest that dissociative symptomatology plays a key role in explaining the relation between PTSD severity and alcohol-related problems. Future studies should examine the impact of targeting dissociative symptomatology specifically in treating individuals with PTSD who endorse alcohol-related problems.

Project description:BackgroundFear responding in posttraumatic stress disorder (PTSD) is sexually heterogeneous and varies with hormonal fluctuations throughout the menstrual cycle. While research suggests that estrogen levels affect PTSD symptoms among women, there is a dearth of research on modulatory effects of estrogen on fear responding among women with PTSD, and neural outcome measures are lacking.MethodsA sample of 42 women with PTSD underwent 2 consecutive alternating blocks of fear conditioning and extinction training, during which a CS+ conditioned stimulus, but not a CS-, predicted the occurrence of an electric shock in an acquisition context but not in an extinction context. Assayed saliva determined estradiol levels. Skin conductance response and whole-brain voxelwise activity during functional magnetic resonance imaging were outcome variables in linear mixed-effects models, with estradiol level, PTSD severity, and task contrasts as predictors.ResultsSkin conductance response exhibited a significant estradiol × PTSD severity × habituation interaction (t = 3.180, p = .002), such that PTSD severity was correlated with increased arousal responding between training blocks among women with lower estradiol (t = -3.985, p < .001) but not higher estradiol (t = 0.550, p = .583). Voxelwise activity also demonstrated an identical three-way interaction within dorsomedial prefrontal cortex and anterior insula clusters. The skin conductance response and imaging interactions between PTSD severity and estradiol were not specific to conditioned stimulus type or context.ConclusionsEstradiol moderated the relationship between PTSD severity and arousal response habituation between fear conditioning and extinction training sessions, such that high estradiol protected against the negative impact of severe PTSD symptoms on fear habituation. These findings suggest that estrogen enhances habituation among women with severe PTSD, potentially influencing the efficacy of extinction-based therapies.

Dataset Information

Fear extinction in traumatized civilians with posttraumatic stress disorder: relation to symptom severity.

Publications

Fear extinction in traumatized civilians with posttraumatic stress disorder: relation to symptom severity.

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