Neurocognitive function in monozygotic twins discordant for combat exposure: relationship to posttraumatic stress disorder

J Abnorm Psychol. 2006 Aug;115(3):484-95. doi: 10.1037/0021-843X.115.3.484.


Neuropsychological deficits have been reported among trauma survivors with posttraumatic stress disorder (PTSD). It is often assumed that these cognitive difficulties are toxic consequences of trauma exposure. Alternatively, they may reflect preexisting characteristics that contribute to the likelihood of developing PTSD. To address this possibility, the authors evaluated cognitive performance in monozygotic twin pairs who were discordant for combat exposure. Pairs were grouped according to whether the combat-exposed brother developed PTSD. The combat-unexposed cotwins of combat veterans with PTSD largely displayed the same performance as their brothers, which was significantly lower than that of non-PTSD combat veterans and their brothers. The results support the notion that specific domains of cognitive function may serve as premorbid risk or protective factors in PTSD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Twin Study

MeSH terms

  • Adult
  • Brain / physiopathology*
  • Cognition Disorders / diagnosis
  • Cognition Disorders / epidemiology*
  • Cognition Disorders / physiopathology*
  • Humans
  • Male
  • Neuropsychological Tests
  • Severity of Illness Index
  • Stress Disorders, Post-Traumatic / diagnosis
  • Stress Disorders, Post-Traumatic / epidemiology*
  • Stress Disorders, Post-Traumatic / psychology*
  • Twins, Monozygotic / psychology*
  • Warfare*