Brain MR identifies youth prone to aberrant behaviors

Cerebral blood flow imaging may eventually help identify young people who need preventive therapy

Adolescents at relatively high risk for depression and alcohol abuse demonstrate distinct patterns of resting cerebral blood flow in areas of the brain associated with emotional behavior and decision making, according to preliminary results from the Research Imaging Center at the University of Texas Health Science Center in San Antonio.

In this ongoing study, researchers are using a pulsed arterial spin-labeling MR sequence to examine differences in CBF in adolescents whose family history puts them at risk for depression and alcohol use disorder. Because earlier studies have shown that the peak period for developing both major depressive disorder and alcohol use disorder occurs between the ages of 15 and 20, doctors at the center are targeting adolescents 12 to 15 years old to investigate differences in CBF at baseline. They hope to define trait markers that indicate the possible development of both conditions.

Douglas E. Williamson, Ph.D., director of the University of Texas genetic epidemiology program, and his team are recruiting 300 adolescents, half with a strong family history of depression, and half with little or no such history.

Preliminary 3T MR results were based on experience with 19 low-risk and nine high-risk subjects. Findings presented by postdoctoral fellow Ai-Ling Lin, Ph.D., at the 2008 International Society for Magnetic Resonance in Medicine meeting showed relatively high resting blood flow in the bilateral amygdala and ventromedial prefrontal cortex for high-risk compared with low-risk subjects. These corticolimbic regions of the brain support emotional behaviors. In the same patients, CBF measured lower in the high-risk subjects in areas of the brain related to decision making: the bilateral insula, right dorsal anterior cingulate cortex, and occipital lobe cuneus.

Lin theorized that the higher CBF in the amygdala and prefrontal cortex raises emotional reactivity and sensitivity to environmental stressors, while the decreased CBF in the other regions signals a poorer integration of the visceral and sensory changes that accompany emotional stress.

"These kids may be sitting around at baseline, hyperaroused and sensitive to emotionally salient cues, and at the same time may be prone to poor decision making," Williamson said.

Based on these initial results, Williamson and Lin expect the ability to identify these trait markers in adolescents to help doctors target preventive intervention therapies for young people who are at risk.

-By Don Rauf