Symptoms of depression, but not PTSD, influence cognitive performance in healthy Army National Guard Soldiers

Research suggests that comorbid depression and PTSD may contribute to cognitive impairment. However, few studies have explored this dynamic in military personnel who report only subclinical symptoms of PTSD and depression.

Army National Guard Soldiers (ARNG; N = 1415) completed the Automated Neuropsychological Assessment Metrics (ANAM), the PTSD Checklist (PCL), and the Center for Epidemiological Studies Depression Scale (CES-D). The effects of PTSD and depression symptoms on ANAM performance were examined using multiple linear regression analyses. Exploratory factor analysis and regression models examined the relationship between symptom clusters and ANAM performance.

Six factors were identified: avoidance/flashbacks, cognitive/social difficulty, depressed mood, positive mood, sleep difficulty, and hypervigilance. Elevated symptoms of depression (measured using factor scores) were associated with poorer attention (β range -0.19-0.18, p range < 0.01-0.04, f² effect size range 0.02-0.94).

Depression symptoms were associated with diminished attentional performance in a large sample of ARNG Soldiers who reported no clinical diagnosis. This study was limited in that unmeasured factors other than depression, PTSD, or demographics may explain much of the variance in cognitive performance. These findings highlight the importance of careful mental health screening and strategies to heighten awareness of the potential detrimental effects of depression and PTSD on health and performance.