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The Roots of Body Dysmorphic Disorder
People who have body dysmorphic disorder (BDD) are often obsessed with certain aspects of their physical appearance which they perceive as "defects." The disorder can be debilitating, as sufferers may spend excessive amounts of time thinking about the perceived problem or looking at the offending feature in the mirror. People with BDD tend to focus on minute details rather than the "big picture," which creates a vast mismatch between one’s perception of oneself and what others see.
Until now, the root of the problem has been unclear. Some researchers have thought that the issue lies within the person’s thoughts, rather than in the brain’s visual processing machinery. But a new study shows that the problem may lie in how the brain takes in visual information.
In the current study, researchers had 14 BDD patients and 14 healthy people look at images of houses that were either very detailed or which had these details (like individual shingles) removed. All participants’ brains were scanned with functional magnetic resonance imaging (fMRI) and compared under the two conditions. The people with BDD had less brain activity in certain visual processing regions when looking at the houses with less detail, compared to the healthy participants. The more severe the BDD, the less holistic processing the brain tended to do.
What exactly does this tell us about the nature of BDD? It’s still unclear whether problems with visual processing lead to BDD or whether it’s the other way round. Study author Jamie Feusner says that the "study suggests that BDD patients have general abnormalities in visual processing. But we haven't yet determined whether abnormal visual processing contributes as a cause to developing BDD or is the effect of having BDD. So it's the chicken-or-the-egg phenomenon."
The study is important because it’s the first to delve into the biological underpinnings of BDD. Though the implications are still not completely clear, Feusner says that the study "is an important step to figuring out what's going wrong in the brains of people with BDD so we can develop treatments to change their perceptions of themselves."
Feusner is a researcher at UCLA, and published the study in the April 18, 2011 online issue of Psychological Medicine.
June 10, 2011