Alan Leshner, Ph.D.
NIH drug leader talks about effects on brain
Drugs of abuse take control of the brain’s normal circuitry, the director of the National Institute on Drug Abuse told the crowd at a special Grand Rounds this week. “Drugs are not working in some special brain system; they’re taking over normal motivational systems,” said Alan Leshner, Ph.D., who has directed NIDA since 1994. NIDA is one of the National Institutes of Health and supports over 85 percent of the world’s research on the health aspects of drug abuse and addiction.
During the special Grand Rounds, sponsored by the department of Neurology and the Vanderbilt Brain Institute, Leshner described how scientific research has improved understanding of the nature of drug abuse and addiction.
With current imaging technologies, like positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), investigators can actually “look into the brain and watch the nature of the drug experience,” he said. These technologies are opening windows on the brain regions and molecules affected by drug use.
People take drugs for two reasons, Leshner said: to feel good – individuals described as novelty or sensation seekers; or to feel better – individuals who are “self-medicating” to overcome depression or anxiety. Whether or not a drug user becomes addicted depends on complex interactions between genetics and environment. “There is a high genetic component to becoming addicted,” he said, and researchers are working to understand the genetic factors and how they work to alter behavior.
“It’s as if there is a switch that flips that turns voluntary drug use into compulsive, addictive drug use,” Leshner said, adding that scientists do not yet know the nature of this switch. Addiction induces fundamental changes in the brain, shifting a person’s priorities so that the drugs of abuse become the top priority, he said. Scientists see similar brain changes in individuals with compulsive behaviors like compulsive eating and gambling.
And recovering from a compulsive disease like addiction depends on an array of medications, counseling, and social support, Leshner said. One of NIDA’s “Millennial Goals” is to improve drug abuse treatment throughout the nation. To better blend research and clinical practice, NIDA has established a national drug abuse treatment clinical trials network that will test new treatment regimes.
Leshner warned that though research has “revolutionized understanding of addiction,” there will be no “magic bullet of medication” that cures the disease. “Science has given us a path and insights, the trick is going to be to have science help us get our strategies right,” he said.
For more information about NIDA and for interactive public education programs directed at parents, teachers, and students, visit the Web site: www.drugabuse.gov.