Early life temperamental anxiety is associated with excessive alcohol intake in adolescence: A rhesus monkey (Macaca mulatta) model

Teenage alcohol abuse is a major health concern, particularly because the majority of alcohol consumed by teenagers is via binge drinking, a known risk factor for increasing the likelihood for the development of future alcohol use disorders (AUDs). Identifying individuals at risk for excessive alcohol intake in adolescence is a step toward developing effective preventative measures and intervention programs. As adults with AUDs tend to self-medicate their anxiety with alcohol, this longitudinal study assesses the role of infant anxiety-like temperament in the development of adolescent alcohol abuse using a nonhuman primate model. From birth until they were 5 months of age, behaviors of 64 rhesus monkeys (Macaca mulatta) were coded twice a week using an objective mother-infant scoring system that included behaviors traditionally used to assess anxiety and fearfulness in rhesus monkeys. When subjects were four months old, plasma cortisol was obtained. When subjects were adolescents (M-age = 44.88 months), another plasma cortisol sample was obtained about one month prior to allowing them unfettered access to an 8.4% (v/v) aspartame-sweetened alcohol solution for one hour a day over five-to-seven weeks. Results showed that behavioral indications of anxiety-like temperament in infancy, including high levels of mother-infant mutual ventral contact, low levels of environmental exploration, and low levels of interactions with peers were predictive of high adolescent alcohol intake (ie, drinking to intoxication). Plasma cortisol levels in infancy were positively correlated with plasma cortisol in adolescence, and both were positively correlated with high adolescent alcohol intake. Our findings indicate that high levels of traditional anxiety-like behaviors measured in the context of mother-infant interactions, coupled with high infant and adolescent plasma cortisol, are associated with binge-like high alcohol intake in adolescence, suggesting that individuals at risk for developing an AUD later in life may be determined, at least in part, by assessing their physiological and behavioral propensity for anxiety early in life.