Neuropsychological correlates of self-reported impulsivity and informant-reported maladaptive behaviour among veterans with posttraumatic stress disorder and traumatic brain injury history.

Objective: Frontal lobe deficits resulting from traumatic brain injury (TBI) and/or posttraumatic stress disorder (PTSD) have been linked to impulsive behaviour. We sought to examine whether neuropsychological performance predicted self-reported impulsivity and informant-reported maladaptive behaviour. Method: We administered the Delis-Kaplan Executive Function System (D-KEFS) to 116 Iraq/Afghanistan-era veterans diagnosed with a history of TBI and PTSD. Results: Poorer performance on D-KEFS Stroop Task (both colour and word, separately) and Trail making (letter sequencing and motor speed) tasks and higher PTSD symptom severity were associated with higher self-reported impulsivity. Trail making letter sequencing performance was negatively associated with informant-reported maladaptive behaviour. Regression analyses revealed PTSD symptom severity and Trail making letter sequencing best predicted self-reported impulsivity, even when accounting for age, sex, and education. Only Trail making letter sequencing predicted informant-reported maladaptive behaviour when accounting for other variables in the model. Conclusions: Attention and processing speed impairments and PTSD symptom severity appear to be important predictors of impulsivity and problematic behaviour among veterans. Findings have implications for theoretical models of aggression and violence and inform the assessment and treatment of individuals with TBI and PTSD.