Pattern of "Scrambled" Neurological Connections a Sign of Anxiety Disorder

December 8, 2009

A team of psychiatrists at Stanford University School of Medicine has discovered that "scrambled connections" in the amygdala may be the "hallmark" of generalized anxiety disorder, or GAD.

A team of psychiatrists at Stanford University School of Medicine has discovered that “scrambled connections” in the amygdala may be the “hallmark” of generalized anxiety disorder, or GAD.

When psychiatry resident Amit Etkin, MD, PhD, and his colleagues examined the basolateral amygdala and the centromedial amygdala subregions of the amygdala, they found that “the two regions still sent emissaries to their separate targets, but the lines of communication were muddled.”

“The basolateral amygdala was less connected with all of its targets and more connected with centromedial targets,” Etkin said. “And the centromedial was less connected with its normal targets and more connected with the basolateral targets.”

In addition, both of these areas of the amygdala were less connected to the part of the brain that determines the importance of stimuli. According to the researchers, this could mean that patients with GAD are less able to differentiate between truly worrisome and mildly annoying situations.

During the study, the researchers examined the brains of 16 patients with GAD and 17 “psychologically healthy participants.” Patients involved in the study underwent functional MRIs. Each spent eight minutes in the scanner, during which they “let their minds wander,” according to the researchers.

Duke University neuroscientist Kevin LaBar, PhD, who did not work on this study, said that these results may be small-scale, but they are an important step in “understanding the brains of people with psychiatric disorders.”

“If we want to distinguish GAD from other anxiety disorders, we might have to look at these subregions instead of the general signal from this area,” LaBar said. “It’s methodologically really impressive.”

According to Etkin, the next step for research in this area is studying the brains of people with other anxiety disorders and depression. This, Etkin said, will allow researchers to determine if connectivity in the amygdala differs “between disorders.”

The study was also published in the Archives of General Psychiatry.