Neural Substrates of Interpreting Emotional Ambiguity in Social Phobia: A Trial-related Functional Magnetic Resonance Imaging Study
2005 Seed Grant
K. Luan Phan, Ph.D.
The University of Chicago
Social anxiety disorder, also known as social phobia, is a severe anxiety disorder characterized by excessive fear and persistent avoidance of exposure to social situations that involve potential scrutiny by others. While the illness is highly prevalent, chronic, disabling, and often co-occur with other major mental disorders, little is known about what is abnormal in the brain of patients with social phobia. Previous psychological research has shown that people with social anxiety have different ways of processing social information. For example, they tend to perceive emotionally ambiguous cues from other people as negative. Through the use of a brain imaging technique called functional magnetic resonance imaging (fMRI), our laboratory has found that some areas of the brain are hyperactive in patients with social anxiety when they view negative (angry, disgusted, fearful) faces in comparison to healthy, non-phobic subjects. One of these hyper-active brain regions, the amygdala, has been known to be involved in processing negative emotions and evaluating potential threat in the environment. However, it is not yet known if the function of this region is associated with the way people process emotionally ambiguous social cues or if it is related to the negative bias in patients with social phobia. This study proposes to use a novel behavioral task and state-of-the science fMRI technology to examine the brain regions involved when people view and interpret ambiguous faces that do not show an obvious emotion. We predict that patients with social phobia will describe these faces as more negative than people without social phobia, and that brain activity in the amygdala and other relevant regions is related to this difference in interpretation or judgment. Discovering the brain areas involved in this mental process and the differences between these two groups will improve our understanding about the neurobiological underpinnings of social anxiety disorder.
In any given year, over 7% of the U.S. population (nearly 15 million people) have social phobia, otherwise known as social anxiety disorder, making it the most common anxiety disorder, and the third most common psychiatric disorder. It begins early in life, lasts chronically, and causes severe functional impairment. People with social phobia tend to be socially isolated and have difficulties in their occupation and in their relationships with other people. The purpose of this research is to advance our understanding of the neurobiology of social anxiety disorder. Anxiety disorders costs the U.S. more than 40 billion dollars each year, due to misdiagnosis and under-treatment. A better understanding of social phobia and its pathophysiology has the potential to improve the way we diagnose, treat, and measure the efficacy of therapies for this devastating major mental illness.