Poor Sense of Smell Linked to Personality Disorder

The sensory impairment is caused by dysfunction in the front part of the brain, researchers say

By Mary Elizabeth Dallas

Thursday, September 27, 2012

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THURSDAY, Sept. 27 (HealthDay News) -- People with psychopathic traits -- such as callousness, manipulation, sensation-seeking and antisocial behaviors -- are not able to use their sense of smell as well as other people can, new research contends.
As a result, the investigators suggest that impaired sense of smell -- or "olfactory" function -- could be a marker for this severe personality disorder. The study, published online Sept. 18 in Chemosensory Perception, noted that the inability to smell is linked to dysfunction in the front part of the brain. Brain dysfunction also negatively affects the ability to plan, control impulses and abide by social norms in people with high psychopathy scores.
"Our findings provide support for the premise that deficits in the front part of the brain may be a characteristic of non-criminal psychopaths," the study authors explained in a journal news release. "Olfactory measures represent a potentially interesting marker for psychopathic traits, because performance expectancies are unclear in odor tests and may therefore be less susceptible to attempts to fake good or bad responses."
In conducting the study, Mehmet Mahmut and Richard Stevenson from Macquarie University in Australia examined 79 people with no criminal history to determine if they had an impaired sense of smell. They also assessed whether or not the study participants had psychopathic behavior, such as erratic lifestyles or criminal tendencies. The researchers also analyzed if the participants were able to empathize with other people's feelings.
The study authors found that the people with the most psychopathic traits were more likely to have trouble identifying or distinguishing between smells. The researchers concluded that the brain areas controlling sense of smell are less efficient in people with psychopathic tendencies.
Although the study found an association between impaired sense of smell and psychopathic behavioral traits, it did not prove a cause-and-effect relationship.

SOURCE: Chemosensory Perception, news release, Sept. 20, 2012

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