In a move to develop a more personalised approach towards medication depending upon genetic information or other biological markers, researchers have shed light on the potential use of functional magnetic resonance imaging (fMRI) to match treatments for patients with generalized anxiety disorder (GAD).

"Personalized medicine" is required as individuals in different groups respond to medications differently not only from individuals of other groups but those of the same group as well.

The researchers led by Dr. Paul Whalen examined subjects diagnosed with GAD who underwent brain scans both before and after treatment with venlafaxine, an antidepressant that has been shown to be effective in treating anxiety. They later measured the participants' responses to viewing pictures of fearful facial expressions during the fMRI scans.

"We focused our study on a regulatory circuit in the brain involving the amygdala, an area that serves to detect the presence of threatening information, and the prefrontal cortex, an area that functions to control these threat responses when they are exaggerated or unnecessary," said Whalen.

The results indicated that almost two thirds of the patients found relief from their anxiety symptoms after treatment, and amongst those who improved, some responded better than others. And according to the hypothesis, the fMRI data predicted who would do well on the drug and who would not.

Whalen said: "subjects who showed high prefrontal cortex activation together with low amygdala activation in response to the fearful faces reported a significant decrease in their anxiety symptoms, while those showing the reverse brain activation pattern (i.e., high amygdala, low prefrontal) did not."

The study was published in Biological Psychiatry.