Depression and cognitive performance in post-9/11 veterans accounting for trauma-related clinical burden.

BACKGROUND

Post-9/11 Veterans experience a disproportionate burden of mental health conditions. Major depressive disorder (MDD) frequently co-occurs with trauma-related conditions, contributing to clinical heterogeneity. Clarifying how categorical and dimensional representations of depression relate to cognition while accounting for clinical comorbidity may improve understanding of depression and inform targeted interventions in Veterans.

OBJECTIVE

To assess how categorical and dimensional measures of depression relate to cognitive performance and clinical characteristics in post-9/11 Veterans.

METHOD: This cross-sectional analysis included 970 U.S. post-9/11 Veterans (ages 18-67) from the Translational Research Center for TBI and Stress Disorders (TRACTS), a multisite longitudinal cohort. Depression was classified via structured clinical interviews as No, Lifetime, or Current Depression. Dimensional measures incorporated recent self-reported, current, and lifetime depression symptom severity. Age-standardized cognitive composites (Global, Memory, Attention, Processing Speed, Executive) were examined in multivariable models adjusting for demographics, estimated premorbid IQ, and clinical and trauma-related symptom burden.

RESULTS

Clinical and trauma-related burden increased progressively from No to Lifetime to Current Depression. Veterans with depression showed no evidence of reduced cognition compared with the non-depressed group. Modest depression-related differences were observed for processing speed, with slower performance in the Current Depression group. Military blast burden significantly moderated the association between depression and processing speed, with slower processing speed in Current Depression most evident at greater military blast burden.

CONCLUSION

These findings suggest that depression is not characterized by broad cognitive impairment in post-9/11 Veterans but that the combination of military blast exposure and depression may subtly affect processing speed.