Scientists have found that cocaine abuse coupled with use of alcohol leads to more impulsive decision-making and to poorer performance on tests of learning and memory than does use of either cocaine or alcohol alone. The negative effects on the ability to think clearly persist for at least a month after the substance use stops, according to an article about the study in the June 27 issue of Neurology.
"This study reveals important basic information about the way these substances interact," says NIDA Director Dr. Alan I. Leshner. "It also has significant implications for drug abuse treatment, which involves learning and remembering concepts that help recovering drug abusers to change behaviors and avoid situations where they might use drugs."
Dr. Jean Lud Cadet, of NIDA's Intramural Research Program in Baltimore, and Dr. Karen Bolla, of Johns Hopkins Medical Institutions in Baltimore, studied the interactive effects of cocaine and alcohol in 56 adult cocaine abusers. Roughly half the study participants also consumed at least 10 alcoholic drinks per week. All participants abstained from both cocaine and alcohol during the four-week study.
During the first three days of the study the participants were given a battery of tests to measure general intelligence, verbal memory and learning, and attention, planning, and mental flexibility. The tests were repeated during the fourth week of the study.
"The results of this study support the view that cocaine abuse can have a major negative impact on the brain and these effects are compounded by the concurrent use of alcohol," explained Dr. Cadet.