In 40 years of research, Marilyn Carroll, a professor in the Department of Psychiatry, has led the way in showing how substituting healthier forms of gratification can reduce drug addiction. With her postdoctoral adviser (Richard Meisch, University of Texas Medical Center, Houston), she discovered evidence that less food availability boosted opiate abuse while increased access to palatable food and liquids reduced it.
“In humans, there is an inverse relationship between food- and drug-rewarded behavior. Food and drugs can substitute for each other she says. “I later extended this finding to other classes of drugs.”
Clues to ending withdrawal and relapse
Carroll and her students and colleagues found that the “reward” of exercise also could prevent and reduce drug-seeking behavior. Based on this, UCLA researchers used exercise to treat addiction to methamphetamine. Exercise during recovery reduced relapse compared to the control condition, where the study volunteers received only general health education.
Carroll and colleagues also found behavioral clues that predict addiction vulnerability, such as more impulsive behavior or preference for sweets, that may signal underlying drug dependence and increase relapse potential. In related work, she found that when drug use ends, there is a period when craving for the drug incubates and grows stronger, ultimately leading to relapse.
Her work also debunked the idea that only excessive or long-term drug abuse can produce withdrawal effects. Addiction takes hold quickly—within hours to days—and endures for weeks, months, or years. Drug use can be reduced or stopped short term, but craving is long term and lack of treatment for addiction during this extended incubation period leads to relapse in most cases.
“This suggests that treatments must be long term and self-motivated, Carroll says. “I have developed novel methods to reduce addiction that can be self-maintained by the drug user over a long period of time to reduce craving and achieve long-term abstinence.”
Based on this work, clinical studies at the University are planned or under way to use exercise to help people reduce or stop using nicotine, marijuana and heroin, and also to test the effectiveness of progesterone (a natural female hormone), alone and in combination with exercise, to reduce drug-seeking and craving.