Current Research
See some of our past publications
Abstracts of current projects, funded by NIDA
1. Drug responses and acute stress
Several ongoing studies investigate interactions between acute stress and drugs of abuse in human volunteers. Stress is closely related to drug abuse, and stress and drugs act on some of the same neurobiological processes. In animal models, acute stress increases drug self-taking, and also changes the direct effects of drugs. In human drug users, stress increases the likelihood of using drugs. We are investigating the effects of acute stress on responses to drugs in controlled laboratory studies. In recent studies, we have compared the effects of stress in men and women, in smokers and nonsmokers, and in women at different phases of the menstrual cycle. In other studies, we have examined the effects of stress on the intoxicating effects of alcohol, or on the desire to smoke cigarettes in smokers. Taken together, these studies will provide a critical translational link between findings from animal studies and clinical observations among drug users. We hope that the studies will help us understand how stress affects drug use, providing information that may lead to improved methods for preventing and treating stress-related drug use.
2. Drug abuse and impulsivity
Drug use is also closely related to impulsivity. Impulsivity increases risk for initiating drug use, continuing drug use despite adverse consequences and for relapse. Conversely, drugs can directly increase impulsive behavior, increasing the probability of risky activities, including continuing to use the drug. We are investigating different types of impulsive behaviors, to identify factors that increase or decrease these behaviors. Measures of impulsivity include assessments of decision-making, behavioral inhibition and attention. In recently completed studies we have investigated the effects of acute stress, sleep deprivation, alcohol, and smoking abstinence on measures of impulsiveness. The projects are designed to improve our understanding how impulsive behavior affects drug use, and how drug use affects impulsivity.
3. Genotypic variations related to drug effects
There is considerable variability in behavioral effects of drugs across individuals, due in part to variations the genes involved in the drugs' sites of action in the brain. In collaboration with Dr. Abe Palmer in the Department of Human Genetics we are studying individual differences in responses to stimulant drugs in relation to polymorphisms in the genes involved in the function of neurotransmitter receptor systems. In recent studies we have reported that the mood-altering effects of single low doses of a stimulant drug are associated with polymorphisms in several genes involved in dopamine, norepinephrine and serotonin function, as well as proteins involved intracellular signaling. These studies demonstrate how pre-existing biological factors can influence the mood-altering effects of drugs, which are likely to influence susceptibility for abuse of the drugs.