|Ability of Behavioral Traits (Temperament) to Predict Response to and Use of Drugs and Alcohol|
|Sunday, May 25, 2014|
|11:00 AM–11:50 AM |
|W175a (McCormick Place Convention Center)|
|Area: BPH/EAB; Domain: Basic Research|
|Chair: Kathleen A. Grant (Oregon Health & Science University)|
|Discussant: Harriet de Wit (University of Chicago)|
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.
|Keyword(s): addiction, aggression, alcohol, delay discounting|
Temperament as a Risk Factor for Heavy Drinking in Male and Female Rhesus Monkeys
|MEGAN MCCLINTICK (Oregon Health & Science University/Oregon National Primate Research Center), Kathleen A. Grant (Oregon Health & Science University)|
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.
|Delay Discounting Predicts Response to Alcohol in Rodents But Not in Social Drinkers|
|SUZANNE H. MITCHELL (Oregon Health & Science University), Travis Moschak (Oregon Health & Science University)|
|Abstract: Individuals with substance use disorders, including alcohol use disorder, tend to prefer smaller, sooner over larger, later rewards (steeper discounting of delayed rewards). This preference may pre-date the development of the disorder, and be mechanistically linked to characteristics that make the development of the disorder more likely. Two studies are described that examine whether sensitivity to delayed rewards, a critical feature of delay discounting, or discounting per se were associated with differential response to alcohol. In one study, rats chose between levers with different delay contingencies (adjusting delay task). Rats were then tested in this task after alcohol administration (0, 0.6, and 0.9 g/kg, i.p.). Operant responding was initially suppressed at the 0.9 g/kg dose. Less suppression was found in animals exhibiting high levels of drug-naïve sensitivity to delay, suggesting that animals with high sensitivity to delay are resistant to the behaviorally suppressant effects of alcohol. A second study examined social drinkers but did not find a significant correlation between drug-free levels of delay discounting and self-reported sedation following an intoxicating dose of alcohol. One possible conclusion is that sensitivity to delayed rewards may predict response in drug-naïve animals but discounting may not be predictive in drug-experienced subjects.|