In Brief

Higher intellectual potential--as measured by intelligence testing--may help safeguard soldiers against developing post-traumatic stress disorder (PTSD), or at least may help reduce the severity of PTSD symptoms.

The finding comes from a recent study led by Jennifer Vasterling, PhD, of the Veterans Affairs Medical Center in New Orleans. She and five other researchers tested attention, memory and learning in 26 Vietnam veterans diagnosed with PTSD and 21 Vietnam veterans without any mental disorders. They also administered the information and vocabulary subtests of the Weschler Adult Intelligence Scale, Revised, to gauge participants' estimated intelligence potential (IQ) before combat.

Participants with PTSD performed more poorly on tasks of sustained attention, working memory and initial learning than did those without the disorder. Meanwhile, those without PTSD--and with less severe PTSD symptoms--earned higher scores on the measure of IQ, which is thought to remain relatively stable over time and is less likely to be influenced by situational and acquired biological factors than other intellectual indices, Vasterling explains.

This suggests that a higher intelligence potential, or IQ, could make soldiers less susceptible to PTSD, says Vasterling, although she notes that the severity of the combat experienced plays the most significant role. Another possibility is that trauma victims with higher IQs may manifest the disorder in a way that's not readily detected by current diagnostic procedures. While acknowledging that some of the soldiers who developed PTSD could have had memory and attention problems before going to war, "based on what we know from the animal literature, there's a good chance that the stress of combat is leading to those problems," Vasterling says.

Why might those with higher IQs have a better chance of escaping PTSD? One reason may be that those with greater IQs tend to have had more education and a better socioeconomic status, making it easier for them to access jobs and other resources that make their post-combat lives less stressful, says Vasterling. Another reason may be that their more sophisticated verbal skills help them cope. "They might be more able to verbalize their negative emotional memories and what they're going through into narratives that are more accessible and understandable to themselves, family and friends," says Vasterling. "That could ease their symptoms."

Thus, she says, an emphasis on coping skills and access to social and economic support appear to be important in treating PTSD. The findings by Vasterling and her team appear in the January issue of APA's journal, Neuropsychology (Vol. 16, No. 1).