Association for Behavior Analysis International

Drug and alcohol use disorders impose heavy personal, familial and societal burdens. Strategies to reduce the prevalence of these disorders have included, but are not limited to, attempts to identify risk factors that detect individuals more likely to develop these disorders. While some attempts have focused on genetics or other biomarkers, others have examined behavioral markers (e.g., temperament/trait variables). This symposium examines individual differences in two such markers: impulsivity (delay discounting) and aggression. Research will be described that examines the ability of these to variables, measured when subjects are in a drug-free or a drug-naive state to predict responses to alcohol or subsequent alcohol drinking. Research will examine several species: rats, nonhuman primates and humans. Discussion will focus on the issues involved when translating findings derived from animal models, as well as larger issues such as the ability of temperament, which may be modified by drug use, to serve as a predictive marker for drug use, and the interaction between responses to a drug and its ability to serve as a reinforcer.

Anxiety and aggressive are frequently associated with alcohol use in humans, though the direction and strength of these associations is unclear. Anxious-like and aggressive-like behaviors were measured in response to a variety of novel stimuli via a human intruder test (HIT) prior to ethanol exposure in 24 rhesus monkeys (11 female, 13 male, macaca mulatta). The HIT reliably assesses differential responses to a human intruder entering the testing room and standing in profile to the monkey (no eye contact), and entering and making direct eye contact with the monkey. Ethanol self-administration was induced via a schedule induced polydipsia procedure, consisting of daily induction of specified volumes of water or 4% ethanol. Subsequently, ethanol (4% w/v) and water were available concurrently 22 h/d. Blood ethanol concentrations (BEC) were determined 7h after the start of the 22h session every 5-7 days. Monkeys characterized as reactive (anxious, aggressive, or anxious-aggressive) at baseline self-administered significantly more ethanol than non-reactive monkeys. Specifically, monkeys aggressive at baseline self-administered significantly more than their non-aggressive counterparts, while no other groups significantly differed. These results indicate that an aggressive but not an anxious temperament in monkeys may serve as a risk factor for future heavy drinking.