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Brain scans reveal differences in the way the brains of individuals with body dysmorphic disorder—a psychiatric condition that causes patients to believe they appear disfigured and ugly—respond to images of their own faces, according to a report in the Archives of General Psychiatry, one of the JAMA/Archives journals.
Body dysmorphic disorder (BDD) affects approximately 1 - 2 % of the population, according to background information in the article.
Patients with the condition become preoccupied with perceived defects in their appearance; many are distressed and cannot function normally, about half are hospitalised at some point in their lifetimes and about one-fourth attempt suicide.
Despite its prevalence and severe effects, little is known about the underlying brain changes that contribute to the disease.
How the study was done
Jamie D. Feusner, M.D., and colleagues at David Geffen School of Medicine, University of California, Los Angeles, assessed 17 patients with body dysmorphic disorder and 16 healthy controls matched by sex, age and education level.
Participants underwent functional magnetic resonance imaging (fMRI) while viewing photographs of two faces—their own and that of a familiar actor—unaltered and then altered in two ways to parse out different elements of visual processing.
One altered version included only high spatial frequency information, which would allow detailed analysis of facial traits (including blemishes and hairs). The other showed only low spatial frequency information, which conveys the general shape of the face and relationships between facial features.
Compared with control participants, individuals with body dysmorphic disorder demonstrated abnormal brain activity in regions associated with visual processing when viewing the unaltered and low spatial frequency versions of their own faces.
They also had unusual activation patterns in their frontostriatal systems, which help control and guide behaviour and maintain emotional flexibility in responding to situations.
What the study revealed
Brain activity in both systems correlated with the severity of symptoms. In addition, differences in activity in the frontostriatal system varied based on participant reports of how disgusting or repulsive they found each image.
The abnormal activation patterns—especially in response to low spatial frequency images—suggest that individuals with body dysmorphic disorder have difficulties perceiving or processing general information about faces.
"Clinically this may account for the impaired ability to perceive the visual gestalt, contributing to distorted perceptions of the individuals' appearance when viewing their face," the authors write.
"The individuals may primarily perceive details and are impaired in their ability to contextualise them configurally or holistically."
Some of the patterns appear similar to those observed in patients with obsessive-compulsive disorder, supporting hypotheses that the two conditions share similar neural pathways. However, future studies are needed to further elucidate the causes and development of body dysmorphic disorder. - (EurekAlert, February 2010)
