THURSDAY, Dec. 16 (HealthDay News) -- Researchers who have studied a woman with a missing amygdala -- the part of the brain believed to generate fear -- report that their findings may help improve treatment for post-traumatic stress disorder (PTSD) and other anxiety disorders.
In perhaps the first human study confirming that the almond-shaped structure is crucial for triggering fear, researchers at the University of Iowa monitored a 44-year-old woman's response to typically frightening stimuli such as snakes, spiders, horror films and a haunted house, and asked about traumatic experiences in her past.
The woman, identified as S.M., does not seem to fear a wide range of stimuli that would normally frighten most people. Scientists have been studying her for the past 20 years, and their prior research had already determined that the woman cannot recognize fear in others' facial expressions.
S.M. suffers from an extremely rare disease that destroyed her amygdala. Future observations will determine if her condition affects anxiety levels for everyday stressors such as finance or health issues, said study author Justin Feinstein, a University of Iowa doctoral student studying clinical neuropsychology.
"Certainly, when it comes to fear, she's missing it," Feinstein said. "She's so unique in her presentation."
Researchers said the study, reported in the Dec. 16 issue of the journal Current Biology, could lead to new treatment strategies for PTSD and anxiety disorders. According to the U.S. National Institute of Mental Health, more than 7.7 million Americans are affected by the condition, and a 2008 analysis predicted that 300,000 soldiers returning from combat in the Middle East would experience PTSD.
"Because of her brain damage, [the patient] appears to be immune to PTSD," Feinstein said, noting that she is otherwise cognitively typical and experiences
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