Researchers Probe Link Between PTSD and IQ
Jan. 30, 2002 -- Verbal skills linked to intelligence may protect people from the lasting effects of a terrible trauma, according to a study of Vietnam War veterans.
Extreme trauma doesn't end when the crisis passes. Only gradually do the effects of an awful event fade away. For some people, the nightmares, the intrusive "flashback" memories, the exaggerated startle responses, and the sleeplessness won't end. This is PTSD -- posttraumatic stress disorder, once known as shell shock.
Not everyone who lives through a traumatic experience gets PTSD. Generally, the more terrible the trauma, the more likely it is a person will get PTSD. It's even more likely to happen to people whose coping skills already are stretched to the limit.
Now research suggests that intelligence may play a role. Jennifer J. Vasterling, PhD, and co-workers at the Veterans Affairs Medical Center, New Orleans, gave verbal intelligence tests to Vietnam War veterans with and without PTSD. Even after taking into account the intensity of their battle experiences, the veterans who did better on the IQ tests were less likely to have PTSD. Veterans who had PTSD despite higher IQ tended to have less-severe PTSD symptoms.
Vasterling suggests that veterans with higher intelligence may have been able to get more support -- in part because they were better able to give words to their experience.
"We think our estimate of intellectual function probably would predict how well you can communicate with other people," Vasterling tells WebMD. "It may predict how well you can use friends or family or community for support. How well you get support depends on how well you communicate. There are theories that suggest the PTSD experience is an overwhelming emotional memory. The more that you can verbalize something like that and talk through your experience, the more it might help. Those are the ways that having greater intellectual resources can help behaviorally."
Having a higher IQ might also help in other ways.
"If you are more intellectual, you are in a better position to get a better-paying job -- so you don't have the kind of stress as someone who's just trying to get a job of any kind," Vasterling says. "Once you are stressed, the stresses you later encounter are going to build on it. You kind of have a downward cycle. The more resources you have to protect yourself the better."
This doesn't mean that smart people don't get PTSD.
"Intellectual function is just one small factor that explains a little of the variance among people who suffer trauma," Vasterling says. "The big variable in whether you get PTSD is how bad, how extreme the stressor is. Intelligence is one little thing that might modulate risk. There are people who are really smart with great resources and great family support, but it was just such a bad thing that happened to them that they have PTSD anyway. That is the sad part of the disorder."