Neuroscience for Kids - Amygdala Smaller in Cocaine Addicts

Smaller Amygdala Size in Cocaine Addicts

November 23, 2004

The Amygdala, Cocaine and Behavior
Magnetic resonance imaging of the brain has revealed that the size of the amygdala in people addicted to cocaine is smaller than the amygdala in healthy adults. The amygdala is an area of the brain that plays a role in drug craving, emotional behavior and reward.
This discovery was made by a team of researchers who studied the brains of 27 people addicted to cocaine and 27 age-matched control subjects. The volumes of the right and left amygdala in cocaine addicts were reduced by approximately 23% and 13%, respectively. The volume of the hippocampus, another area of the brain measured by the scientists, was not different in the two groups.

Cause or Effect?
It is not known if cocaine causes the amygdala to shrink or if a small amygdala size increases the risk that people will become addicted to cocaine. Also, researchers do not know if people addicted to other drugs also have smaller amygdala sizes. If it turns out that a smaller amygdala size increases the risk that a person will become addicted to drugs, it may be possible for people to get a brain scan to examine the amygdala. Such a test might identify people at risk for drug addiction.

Reference and further information:

Makris, N., Gasic, G.P., Seidman, L.J., Goldstein, J.M., Gastfriend, D.R., Elman, I., Albaugh, M.D., Hodge, S.M., Ziegler, D.A., Sheahan, F.S., Caviness, V.S., Jr., Tsuang, M.T., Kennedy, D.N., Hyman, S.E., Rosen, B.R. and Breiter, H.C. Decreased absolute amygdala volume in cocaine addicts. Neuron, 44:729-740, 2004.
Cocaine and the Nervous System

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