Less is more: Smaller hippocampal subfield volumes predict greater improvements in posttraumatic stress disorder symptoms over 2 years.

Posttraumatic stress disorder (PTSD) is a heterogeneous disorder, and symptom severity varies over time. Neurobiological factors that predict PTSD symptoms and their chronicity remain unclear. This study investigated whether the volume of the hippocampus and its subfields, particularly cornu ammonis (CA) 1, CA3, and dentate gyrus, are associated with current PTSD symptoms and whether they predict PTSD symptom changes over 2 years. We examined clinical and structural magnetic resonance imaging measures from 252 trauma-exposed post-9/11 veterans (159 with Time 1 PTSD diagnosis) during assessments approximately 2 years apart. Automated hippocampal subfield segmentation was performed with FreeSurfer Version 7.1, producing 19 bilateral subfields. PTSD symptoms were measured at each assessment using the Clinician-Administered PTSD Scale-IV (CAPS). All models included total intracranial volume as a covariate. First, similar to previous reports, we showed that smaller overall hippocampal volume was associated with greater PTSD symptom severity at Time 1. Notably, when examining regions of interest (CA1, CA3, dentate gyrus), we found that smaller Time 1 hippocampal volumes in the bilateral CA1-body and CA2/3-body predicted decreased PTSD symptom severity at Time 2. These findings were not accounted for by combat exposure or treatment history. Additionally, both Time 1 CA1-body and CA2/3-body volume showed unique associations with changes in avoidance/numbing, but not with changes in reexperiencing or hyperarousal symptoms. This supports a more complex and nuanced relationship between hippocampal structure and PTSD symptoms, where during the posttrauma years bigger may not always mean better, and suggests that the CA1-body and CA2/3-body are important factors in the maintenance of PTSD symptoms. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Inhibitory control and alcohol use history predict changes in posttraumatic stress disorder symptoms.

OBJECTIVE: Posttraumatic stress disorder (PTSD) is associated with significant disability and can become chronic. Predictors of PTSD symptom changes over time, especially in those with a PTSD diagnosis, remain incompletely characterized. METHOD: In the present study, we examined 187 post-9/11 veterans (Mage = 32.8 years, 87% male) diagnosed with PTSD who performed two extensive clinical and cognitive evaluations approximately 2 years apart. RESULTS: We found that greater PTSD symptom reductions over time were related to lower lifetime drinking history and better baseline inhibitory control ability (Color-Word Inhibition and Inhibition/Switching), though not performance on other executive function tasks. Further, groups with reliably Improved, Worsened, or Chronic PTSD symptoms demonstrated significant differences in baseline inhibitory control and lifetime drinking history, with marked drinking differences starting in the early-to-mid 20s. We also found that PTSD symptom changes showed little-to-no associations with changes in inhibitory control or alcohol consumption. CONCLUSIONS: Together, these findings suggest that, in those diagnosed with PTSD, inhibitory control and alcohol use history reflect relatively stable risk/resiliency factors predictive of PTSD chronicity. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Poorer Inhibitory Control Uniquely Contributes to Greater Functional Disability in Post-9/11 Veterans.

OBJECTIVE: Post-9/11 Veterans endorse greater self-reported functional disability than 80% of the adult population. Previous studies of trauma-exposed populations have shown that increased post-traumatic stress disorder (PTSD) and depressive symptoms are consistently associated with greater disability. Additionally, poorer cognitive performance in the domain of executive functions, particularly inhibitory control, has been associated with disability, though it is unclear if this effect is independent of and/or interacts with PTSD and depression. METHOD: Three overlapping samples of n = 582, 297, and 183 combat-deployed post-9/11 Veterans completed comprehensive assessments of executive functions, PTSD and depressive symptoms, and self-reported World Health Organization Disability Assessment Schedule-II (WHODAS II). RESULTS: Poorer performance on measures of inhibitory control (Delis-Kaplan Executive Functioning System Color-Word Interference-CWI Test and gradual-onset Continuous Performance Test-gradCPT), but not other executive functions, were significantly associated with greater disability on the WHODAS II (ρ's = -.13 and -.13, p = .002 and .026, respectively). CWI inhibitory control measures accounted for unique variance in disability after controlling for PTSD and depressive symptoms (R2 change = 0.02, p < .001). Further, CWI significantly moderated the effect of depressive symptoms on disability, such that better inhibitory control weakened the relationship between depression and disability. CONCLUSIONS: Inhibitory control deficits are uniquely associated with increased disability in combat-deployed post-9/11 Veterans, and better inhibitory control abilities may serve as a protective factor for depressive symptoms leading to increased disability.