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A growing number of studies have examined alterations in white matter organization in people with posttraumatic stress disorder (PTSD) using diffusion MRI (dMRI), but the results have been mixed which may be partially due to relatively small sample sizes among studies. Altered structural connectivity may be both a neurobiological vulnerability for, and a result of, PTSD. In an effort to find reliable effects, we present a multi-cohort analysis of dMRI metrics across 3047 individuals from 28 cohorts currently participating in the PGC-ENIGMA PTSD working group (a joint partnership between the Psychiatric Genomics Consortium and the Enhancing NeuroImaging Genetics through Meta-Analysis consortium). Comparing regional white matter metrics across the full brain in 1426 individuals with PTSD and 1621 controls (2174 males/873 females) between ages 18-83, 92% of whom were trauma-exposed, we report associations between PTSD and disrupted white matter organization measured by lower fractional anisotropy (FA) in the tapetum region of the corpus callosum (Cohen's d = -0.11, p = 0.0055). The tapetum connects the left and right hippocampus, for which structure and function have been consistently implicated in PTSD. Results were consistent even after accounting for the effects of multiple potentially confounding variables: childhood trauma exposure, comorbid depression, history of traumatic brain injury, current alcohol abuse or dependence, and current use of psychotropic medications. Our results show that PTSD may be associated with alterations in the broader hippocampal network.

This study explored the extent to which emotion regulation dimensions statistically mediate the association between sleep disturbance and suicide risk among firefighters. Participants were 865 firefighters working for a fire department in an urban area in the southern U.S. Bootstrapping was used to test the indirect effects of sleep disturbance on suicide risk through emotion regulation dimensions, after controlling for depression and trauma exposure The effect of sleep disturbance on suicide risk was significantly statistically mediated by emotion regulation difficulties (β=.09, SE =.02, 95% CI:.05,.14). Moreover, each of the five dimensions of emotion regulation difficulties significantly statistically mediated this association, with difficulties in engaging in goal-direct behavior (β =.09, SE =.02, 95% CI:.05,.14) and lack of strategies to reduce distress demonstrating the strongest indirect effects (β =.07, SE =.02, 95% CI:.04,.11), after accounting for depression and trauma exposure. Results suggest that suicide interventions for firefighters who suffer from sleep disturbance should focus on the development of emotion regulation strategies. [ABSTRACT FROM AUTHOR]

Firefighters demonstrate high rates of posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD). Research has yet to compare how these diagnoses and their co-occurrence relate to firefighter mental health. This study evaluated trauma load, PTSD, alcohol use, depression, sleep, suicide risk, anger, and occupational stress across four discrete groups of firefighters (N = 660): (1) trauma-exposed only (n = 471), (2) probable PTSD-only (n = 36), (3) probable AUD-only (n = 125), and (4) probable PTSD-AUD (n = 28). Firefighters completed an online survey. Firefighters with probable PTSD-AUD demonstrated higher scores on all criterion variables, except trauma load, compared to firefighters with probable AUD-only or trauma-only. Firefighters with probable PTSD-AUD and probable PTSD-only reported similar levels of all indices, except alcohol use severity and suicide risk, which were higher among the probable PTSD-AUD group. Results provide preliminary empirical evidence of the deleterious impact of PTSD-AUD comorbidity among firefighters. [ABSTRACT FROM AUTHOR]

This study compared across Hispanic and Caucasian firefighters the relative fit of the four-factor Emotional Numbing and Dysphoria posttraumatic stress disorder models to the more recently proposed Dysphoric Arousal five-factor model. As hypothesized, the Dysphoric Arousal five-factor model emerged as the best fitting model within each ethnic group and it also showed measurement invariance between groups (configural invariance). Results of multigroup confirmatory factor analyses and a bias-corrected bootstrap confidence intervals analytic approach indicated that the five factor model also demonstrated invariance in factor loadings (metric invariance) and item-level intercepts (scalar invariance) across the two ethnic groups. Results indicate that the Dysphoric Arousal five factor model captures similar psychological constructs across Caucasian and English-speaking Hispanic firefighters. Therefore, observed factor scores are comparable across ethnic groups and can be combined when examining predictors of posttraumatic stress disorder severity. [ABSTRACT FROM AUTHOR]