Adolescence and early adulthood are periods of growth, exploration, and—for some teens and young adults—the development of drug abuse and addiction. Each day roughly 3,000 teens smoke their first cigarette. Among 30,000 teenagers polled by the National Survey on Drug Use and Health in 2002, 4.2 percent of 12- to 13-year-olds reported using an illicit drug in the past month, along with 11.2 percent of 14- to 15-year-olds, 19.8 percent of 16- to 17-year-olds, and 22.5 percent of 18- to 20-year-olds. Data gathered in 2002 by the Substance Abuse and Mental Health Services Administration show that 64 percent of patients entering treatment for drug abuse started abusing drugs at age 20 or younger.

Teen smoking illustrates the risks of early exposure to addictive drugs. A third of high school students who try smoking eventually become daily smokers. Young smokers appear to be more vulnerable to nicotine addiction than are older smokers; teen users report symptoms of dependence after smoking fewer cigarettes than adults, and they have more difficulty quitting and experience more severe withdrawal than adults who smoke similar amounts.

NIDA research is shedding light on the processes that underlie the exceptional susceptibility to addiction experienced by boys and girls who begin using drugs in adolescence. Recent animal studies provide evidence that drugs affect the developing brain differently than they do the matured brain. In one study, rats exposed to nicotine in adolescence self-administered more nicotine—as adolescents and as adults—than rats first exposed to nicotine in adulthood. In another study, rats exposed to nicotine in adolescence and given cocaine when they reached adulthood exhibited more sensitivity to cocaine's stimulant effects than did rats that were first exposed to both drugs as adults (see "Early Nicotine Initiation Increases Severity of Addiction, Vulnerability to Some Effects of Cocaine," NIDA NOTES, Vol. 19, No. 2).

To strengthen prevention and treatment of drug abuse and addiction during the crucial adolescent period, NIDA has initiated a three-pronged research effort. One component of the effort will explore how developmental changes that occur in the adolescent brain may increase vulnerability to drugs, and how drugs in turn may subvert normal neurobiological maturation. We will increase support of animal studies to ascertain the successive steps in adolescent brain development and whether they differ with abstention from drugs, initiation of drug abuse, escalation to uncontrollable abuse, and relapse (RFA 04-011: "Animal Models of Adolescent Drug Abuse: Integrative Studies of Brain and Behavioral Development").

A second component of our initiative aims to increase our ability to dissuade teens from abusing drugs by focusing on the cognitive processes—learning, motivation, judgment, and decision making—that influence choices to abuse or avoid drugs (RFA 04-009: "Behavioral and Cognitive Processes Related to Adolescent Drug Abuse"). This research will elucidate how teens perceive risk and make decisions on matters that involve risk. It will address such questions as why some young people engage in drug abuse when they have received information regarding its destructive potential. Do they assess the risks inaccurately, or do they understand the risks but weigh them more lightly than do abstaining adolescents?

The third focus of NIDA's new initiative is the period of emerging adulthood, which spans the years from 18 to 25. This is a time of continued brain development, but most of all of new personal and social choices and challenges: the emergence of personal beliefs and values, exploration of career roles, and transitions involving increasing independence and shifts in relationships with parents and peers. Overall rates of drug use peak and begin to subside during these years. Most youths who abuse drugs in their teens or early twenties desist as they mature into full adults, but some do not and some initiate new abuse of additional drugs: About 25 percent of smoking, 33 percent of marijuana use, and roughly 70 percent of cocaine abuse begins after age 17. Personal, social, and demographic factors such as education, employment, and home environment all appear to influence the patterns of abuse in this period.

NIDA's sharpened focus on emerging adults will support development and testing of interventions to prevent initiation or escalation of drug abuse during this life transition (RFA 04-013: "Prevention Research for the Transition to Adulthood"). The research will draw on a broad array of academic disciplines to generate and evaluate strategies of intervening on factors ranging from interpersonal relationships— the negative influence of one intimate partner on the drug use of the other, for example—to broader social contexts, such as workplaces and college campuses.

The choices adolescents make have a profound impact. NIDA's intensified concentration on the interaction of drugs and adolescent development will sharpen our understanding of those crucial choices, and will help us provide adolescents with the information they need to choose wisely.

Volume 19, Number 3 (September 2004)