Journal of the International Neuropsychological Society

Research Articles

Impaired Response Inhibition in Veterans with Post-Traumatic Stress Disorder and Mild Traumatic Brain Injury

Diane Swicka1 c1, Nikki Honzela1, Jary Larsena1, Victoria Ashleya1 and Timothy Justusa1

a1 Research Service, Veterans Affairs Northern California Health Care System, Martinez, California and Department of Neurology, University of California, Davis, California


Combat veterans with post-traumatic stress disorder (PTSD) can show impairments in executive control and increases in impulsivity. The current study examined the effects of PTSD on motor response inhibition, a key cognitive control function. A Go/NoGo task was administered to veterans with a diagnosis of PTSD based on semi-structured clinical interview using DSM-IV criteria (n = 40) and age-matched control veterans (n = 33). Participants also completed questionnaires to assess self-reported levels of PTSD and depressive symptoms. Performance measures from the patients (error rates and reaction times) were compared to those from controls. PTSD patients showed a significant deficit in response inhibition, committing more errors on NoGo trials than controls. Higher levels of PTSD and depressive symptoms were associated with higher error rates. Of the three symptom clusters, re-experiencing was the strongest predictor of performance. Because the co-morbidity of mild traumatic brain injury (mTBI) and PTSD was high in this population, secondary analyses compared veterans with PTSD+mTBI (n = 30) to veterans with PTSD only (n = 10). Although preliminary, results indicated the two patient groups did not differ on any measure (p > .88). Since cognitive impairments could hinder the effectiveness of standard PTSD therapies, incorporating treatments that strengthen executive functions might be considered in the future. (JINS, 2012, 18, 1–10)

(Received August 20 2011)

(Revised March 11 2012)

(Accepted March 12 2012)


c1 Correspondence and reprint requests to: Diane Swick, VA Northern California Health Care System, Research Service (151), 150 Muir Road, Martinez, CA 94553. E-mail:

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