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NIDA. (1995, December 1). Finding and Defining Causes of Drug Abuse. Retrieved from

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December 01, 1995
Robert Mathias and Neil Swan
NIDA's Addiction Research Center (ARC) 60th Anniversary

The Etiology Branch conducts studies to determine and define the causes, mechanisms, and conditions that lead to drug use and drug dependence. The branch collects and analyzes findings on the many complex and interrelated causes of drug use and dependence so that these findings can readily be translated into strategies for drug abuse prevention and treatment.

The Etiology Branch's research focuses on the biobehavioral aspects of vulnerability and resilience: Why is it that although many people are exposed to illicit drugs, only a minority develops serious drug abuse and dependence problems? How do an individual's unique character, personality, and other traits work together with that person's upbringing and environment in ways that might foster drug-taking behavior?

Dr. Mark GreenwaldDr. Mark Greenwald measures activity in response to a test environment. The experiment helps determine how much novelty-seeking behavior in novel environment can predict psychostimulant response.

Another key challenge is to identify the physical and psychological mechanisms and risk factors that promote progression from experimental drug use to full-fledged drug dependence. Several mechanisms that lead at-risk people to become drug dependent have been studied recently or are currently under study. They include attention deficits in childhood, aggressive-impulsive behavior in adolescents and adults, the processes involved in becoming "conditioned" to drug use, individual differences in responses to drug-use incentives, abnormal responses to common drugs, and the consequences of easy access to drugs.

"Laboratory studies of the behavioral characteristics of drug takers and their responses to drugs can help us find centrally important determinants of drug taking," says Acting Branch Chief Dr. James C. Anthony. He and other researchers try to find those behavioral, physiological, and other responses that can be used as markers in predicting vulnerability to drug dependence.

What factors promote progression from initial use of drugs to drug abuse and dependence?

One recent study examined how volunteers respond to amphetamine in a recreational environment. Similar to studies with rats, this research shows that the same volunteers who demonstrate the greatest increase in spontaneous motor activity when first exposed to the test environment also show the greatest amphetamine-induced increase in motor activity. Thus, the extent to which experience-seeking behavior in a novel recreational environment predicts psychostimulant response and drug-taking is an important question for future study.

Another investigation, of drug-abusing women and their babies, is evaluating the effects of prenatal cocaine exposure. The ability of premature, low-birth-weight newborns to tolerate the stressful conditions of the hospital intensive care environment is evaluated. Cocaine-exposed newborns will be compared to premature newborns who are either exposed to other illicit drugs or not exposed to drugs.

The branch also analyzes epidemiological data from diverse sources for clues to drug-use risk factors and protective factors. In one epidemiological study of newborns followed to late childhood, the branch is evaluating the extent to which poor maternal supervision and monitoring might be explained by maternal drug dependence or comorbid psychiatric disturbances. The study explores mechanisms linking poor parental supervision to later increased vulnerability to drug abuse in late childhood and early adolescence.