Nicotine sensitizes the mouse brain to the addictive effects of cocaine, according to recent NIDA-supported research. The results accord with the hypothesis that a person’s initial use of an addictive substance physiologically sensitizes his or her brain to the rewarding and addictive effects of other substances. If the findings carry over to people, then preventing youths from smoking might reduce their vulnerability to cocaine abuse and addiction, and cocaine-dependent individuals might ease their path to recovery by quitting smoking.
The immune system has an extraordinary ability to recognize compounds foreign to the body and eliminate them. NIDA-sponsored scientists are working to harness this ability to create vaccines that will protect individuals against the psychogenic and addictive effects of abused drugs. This animation shows one of the most promising strategies, which has already yielded partial success in producing effective vaccines against nicotine, cocaine, and other drugs.
NIDA-supported research suggests that glucocorticoid receptor levels during early brain development affect the hard wiring of neural circuits that shape an individual’s basic emotional makeup. In mice, overexpression of the glucocorticoid gene in the first weeks after birth increased anxiety and response to cocaine in adulthood. These findings may help researchers understand the genetic background and the developmental trajectory of addiction.
New vaccines that aim to promote recovery from cocaine and heroin abuse showed promise in animal testing. Both vaccines induced rats’ immune system to produce high titers of antibodies that inhibit the target drug from reaching the brain. The rats’ behaviors when given access to the target drug indicated that the vaccines reduced the reinforcing effects that, in recovering people, can cause lapses to turn into relapses.
Prenatal drug exposure can have behavioral effects that last well into adulthood, according to two studies of adult monkeys prenatally exposed to cocaine. In the first study, drug-exposed monkeys exhibited less flexibility than controls in adjusting to changing circumstances; in the second study, drug-exposed males exhibited a greater preference than controls for having rewards right away, a sign of impulsivity.
Dr. J. David Jentsch is the recipient of the 2011 Jacob P. Waletzky Memorial Award for Innovative Research in Drug Addiction and Alcoholism. Dr. Jentsch and colleagues at the University of California, Los Angeles, are studying genetic and neurochemical factors that influence individual differences in inhibitory control.
Illicit drug use in the United States in 2010 was at its highest level since 2002, according to the most recent report from the National Survey on Drug Use and Health. A rise in marijuana use drove the increase. A favorable trend of falling cocaine use continued.