Association of intelligence with severity of posttraumatic stress disorder symptoms in Vietnam Combat veterans

OBJECTIVE: The purpose of this study was to determine whether intelligence predicts variance in posttraumatic stress disorder (PTSD) symptoms beyond that predicted by extent of combat exposure. METHOD: The subjects were 105 male Vietnam combat veterans. They completed the Mississippi Scale for Combat-Related Posttraumatic Stress Disorder, the Combat Exposure Scale, and the Shipley Institute for Living Scale, a measure of general intelligence. Number of years of education was recorded for each subject. RESULTS: Multiple regression analyses revealed that estimated full-scale IQ significantly predicted variance in PTSD symptoms beyond that predicted by extent of combat exposure. The lower a subject's intelligence, the more severe were his PTSD symptoms. CONCLUSIONS: Cognitive variables may affect the ability to cope with trauma, thereby affecting whether a person develops chronic PTSD.