Contributory Etiologies to Cognitive Performance in Multimorbid Post-9/11 Veterans: The Deployment Trauma Phenotype.

Objective: This study examined cognitive functioning in post-9/11 Veterans with the deployment trauma phenotype (DTP), comprised of co-occurring diagnoses of depressive disorder (major depressive disorder and or persistent depressive disorder/dysthymia), posttraumatic stress disorder (PTSD), and mild traumatic brain injury (mTBI), using objective neuropsychological measures.

Method: Participants included a cross-sectional sample of 399 post-9/11 Veterans who completed clinical interviews and neuropsychological tests as part of a larger study at VA Boston Healthcare System. Confirmatory factor analysis identified four cognitive domains: attention, cognitive control/processing speed, episodic memory, and cognitive flexibility. Veterans with DTP and its constituent diagnoses in isolation, two-way diagnostic combinations, and no constituent diagnoses were compared.

Results: Veterans with DTP had a twofold increased prevalence for below average performance in cognitive control/processing speed compared with those with no constituent diagnoses (prevalence ratios [PRs] = 2.04; 95% confidence interval [CI]: 1.03-4.05). The PTSD + depressive disorder group also had a twofold increased prevalence for below average performance in episodic memory (PR = 2.16; 95% CI: 1.05-4.43).

Conclusions: The deployment trauma phenotype is associated with clinically significant decrease in cognitive control/processing speed in post-9/11 Veterans. Comorbid PTSD and depressive disorder negatively impacted performances in episodic memory. Mild TBI alone showed no cognitive deficits. Clinical interventions should target psychiatric symptoms with a transdiagnostic approach to address this multimorbid population.