The claim that an anxiety disorder could make Oscar Pistorius more likely to fight a threatening situation than flee it is plausible but hard to prove, experts say.
A judge ordered psychiatric testing for the Olympian accused of murdering his girlfriend, Reeva Steenkamp, after Dr. Merryll Vorster testified that Pistorius has general anxiety disorder, a psychiatric condition that could make him more likely to fight a threatening situation than flee it.
"You're looking for things... that would supercharge that nervous system and leave it more vulnerable," said George Everly, associate professor of Psychiatry and Behavioral Sciences at the Johns Hopkins University School of Medicine. "You can have chronic exposure or traumatic event -- either one works."
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Some people with the disorder have a genetic history or have experienced traumatic events that make them "hyper-sensitive" to perceived threats, Everly said. In severe cases, people can feel so afraid that they want to protect themselves in seemingly overzealous ways, he said, from installing extra security alarms to amassing weapons.
"Think of a lightning bolt going through electric currents [of the brain]," he said. "The result is a sensitization... you get a sense of a person walking around, they're hyper-sensitive to everything. Everything is magnified, specific fears are magnified."
Everly said experts testing Pistorius will look for a family history of the anxiety disorder as well as exposure to trauma or anxiety-inducing events before forming a diagnosis. For a person with severe general anxiety disorder, Everly said it's certainly plausible that they acted irrationally because they were so fearful of perceived threats.
"If generalized anxiety disorder is to be used effectively [in the trial], it must demonstrate that it created a potential for a biological hyper-sensitivity... or lead to a learned pattern of physical and psychological overreaction," he said.
But without proof of that biological hyper-sensitivity, Everly said the Pistorius defense team may be "sitting there in the water without a paddle."
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