Advances in science in recent decades have revolutionized the understanding of the nature of drug abuse and addiction and what society needs to do about them. Alan Leshner, chief executive officer of the American Association for the Advancement of Science (AAAS), says there is now a clear understanding that drug abuse and addiction are bio-behavioral phenomena with important biological, behavioral and social-context components. Those components must be recognized in developing prevention, treatment and social-policy responses to the problems.

According to Leshner, two decades of research have spelled out in great detail the brain mechanisms by which each drug of abuse changes mood, perception or emotional state. Virtually every drug of abuse elevates levels of the neurotransmitter dopamine in the brain pathways that control the experience of pleasure. Prolonged use of these drugs actually changes the brain in fundamental and long-lasting ways. In effect, drugs of abuse take over the brain's normal pleasure and motivational systems, moving drug use to the highest priority in the individual's motivational hierarchy, overriding all other motivations and drives. Moreover, these brain and behavioral changes persist long after the individual has stopped using drugs.

Leshner says that addiction is a not only brain disease but also is a result of a combination of historical and environmental factors, and physiology. Research shows that comprehensive treatments that focus on the whole individual, and not just on drug use, have the highest success rates. These programs provide a combination of behavioral treatments, medications and other services, such as referral to medical, psychological, and social services. Scientific discoveries also are fueling the development of more successful strategies to deal with addicted criminal offenders. The core phenomenon, Leshner says, is that untreated addicted offenders have extremely high rates of post-release recidivism both to drug use and to criminality. However, providing science-based treatments while offenders are under criminal-justice control can dramatically reduce recidivism, again both to drug use and later to crime.

Leshner discussed his research during a lecture at the Library in April 2008. The program can now be found as a webcast on the Library’s Web site. The lecture was sponsored by the Library’s Science, Technology and Business Division. For more resources on the science of addiction, the division provides several tools, including an Internet resource list; a Reference Guide; and a Science Tracer Bullet on the subject of the brain.