Reduced Amygdala Activation in Young Adults at High Risk of Alcoholism: Studies from the Oklahoma Family Health Patterns Project

Background: Risk of alcoholism is higher in those with a positive family history (FH+) and in those showing behavioral disinhibition, possibly reflecting altered limbic system function. Methods: We performed functional magnetic resonance imaging (fMRI) in 17 nonabusing young adults, 9 with FH+ and high in disinhibition versus 8 with a negative family history (FH-) and low in disinhibition. We probed limbic system reactivity with a recognition task using faces expressing fear versus geometric objects. Results: Subjects with FH- had robust activation to the faces in the region of the right and left amygdalar complexes (p's < .05), while subjects with FH+ had no such activation (p's > .46). The blood oxygenation level-dependent (BOLD) signal in the region of the amygdala was correlated with scores on the self-report measure of temperament in the combined groups (r = .51, p < .04). Conclusions: Behaviorally disinhibited temperament, found in many with FH+, may be associated with amygdalar hyporesponsiveness and a failure to avoid risky decisions, increasing the person's liability for alcohol abuse.