Project Summary/Abstract Adolescence is a period of heightened susceptibility to cocaine addiction. Certain aspects of addiction are also more severe in females than in males. Several factors have been proposed to mediate such heightened susceptibility in adolescents and females. What is unknown is if adolescents and females are less sensitive to conditions of external adversity associated with the process of obtaining cocaine. Perseveration of drug seeking and taking despite adversity and hazardous conditions is a hallmark of addiction, and has been hypothesized to be a key factor underlying susceptibility to develop addiction. The hypothesis of this proposal is that adolescents and females are less sensitive to adverse events required to obtain cocaine. Surprisingly, this hypothesis has not been tested extensively. Testing this hypothesis is important because it would underline that adolescents and females are a vulnerable population and provide an important reason as to why that is. This hypothesis will be tested by modifying an existing test, whereby rats need to surmount an ?aversive obstacle? in order to obtain cocaine. The aversive obstacle is in the form of an electric barrier (a portion of electrified floor) that rats need to traverse to obtain the drug. The intensity of the electricity is increased incrementally, until the rats reach abstinence. Ages (adolescents and adults) and sexes (males and females) will be compared for their ability to suppress cocaine intake in conditions of increased adversity to obtain the drug. The project is innovative in what it studies (age- and sex-differences in taking cocaine in conditions of adversity to obtain the drug). It is also innovative in the manner in which it implements and modifies an existing behavioral model to test the pursuit of drug taking despite adversity associated with the process of obtaining the drug. The project is significant, as it will provide important insight into understanding the nature of adolescent and female susceptibility to addiction.