Olfactory identification in combat-related posttraumatic stress disorder.

Recent neuropsychological conceptualizations of posttraumatic stress disorder (PTSD) implicate dysfunction of the fronto-limbic system, a brain system thought to be involved in the mediation of emotion. However, few studies have examined fronto-limbic subregions, such as the orbitofrontal cortex, in PTSD. As a measure of orbitofrontal integrity, olfactory identification was assessed in 26 Vietnam War veterans with PTSD, 25 Vietnam War veterans without mental disorders, and 17 Vietnam-era, non-war-zone veterans without mental disorders. Relative to veterans without PTSD, those diagnosed with PTSD were less proficient in odor identification and verbal learning but not on other cognitive tests sensitive to dorsolateral prefrontal and mesial temporal functioning. Results bolster prior research indicating fronto-limbic dysfunction in PTSD, and suggest involvement of the orbitofrontal region.