Our Center, established in 1987, was the first prevention center to be funded by the National Institute on Drug Abuse. A consistent but certainly not exclusive focus of research conducted in the Center has been on elucidating the role of sensation seeking behavior in the onset and development of drug abuse, and in applying this information for the development of more focused and efficacious prevention programs. As defined by Zuckerman's scale, sensation seeking refers to the personality trait characterized by a need for stimulation, which is related to a preference for novel and complex stimuli.
During the initial funding phase of the Center, three projects evaluated sensation or novelty seeking at complementary levels of analysis. The first project (Bardo and colleagues) developed an animal model of novelty seeking behavior in which individual differences in psychomotor activity and exploratory behavior associated with novel environments and objects were measured. This model has proven to be valid with respect to drug use in that measures of novelty seeking are predictive of individual differences on several indices of drug abuse liability, including psychomotor reactivity, drug discrimination and drug reward in rats. Continuously funded since the inception of the Center, this project has enabled us to evaluate neurobiological substrates of novelty seeking. Using neurochemical techniques, George Rebec at Indiana University and Linda Dwoskin at Kentucky have provided evidence that novelty seeking behavior is associated with activity within the mesolimbic and mesocortical dopamine systems.
In the second project funded during the initial phase of the Center (Clayton and colleagues), the sensation seeking levels and reported drug use of five consecutive cohorts of 6th graders in Lexington, Kentucky, were measured in the course of evaluating the efficacy of the universal drug-abuse prevention program, Project DARE. The principal conclusion was that DARE has no sustained effects on drug use or any of the putative mediating variables, thus yielding no efficacy. However, this study reaffirmed the strong association between sensation seeking and drug use, as clear and sustained links between sensation seeking and drug use were observed, even in relatively young adolescents. Longitudinal follow-ups of these cohorts were continued in subsequent phases of the Center (Leukefeld and colleagues), and the link between sensation seeking status and drug abuse has been further strengthened. These follow-up studies have demonstrated that the development of problems associated with drug use in older adolescents and young adults are also closely linked to sensation seeking status. Subjects from these cohorts have also been recruited as young adults into our controlled behavioral pharmacology laboratory (Kelly and colleagues), where we are assessing the role of sensation seeking status on the behavioral and physiological effects of drugs.
The third project funded during the initial phase of the Center (Donohew and colleagues) evaluated the effects of the content of televised messages designed to prevent drug abuse. Justification for this project was established, in part, because of the close link between sensation seeking behavior and drug use. Since sensation seeking status was clearly linked to drug use, this personality dimension provided the means for developing a functional strategy for the selective targeting of public service announcements (PSAs) to at-risk populations. This strategy involved manipulating the sensation value of messages (i.e., the degree to which a message elicits sensory, affective and arousal responses). During the initial phase of the Center, the sensation-value of anti-drug PSAs, as well as of programs in which the PSAs were embedded, were manipulated in experiments comparing the responses of high and low sensation seekers. These early laboratory-based studies established that high sensation-value content in PSA messages presented during high sensation value programs were most effective for influencing the attitudes of high sensation seekers. This line of research has been continued with several funded R01s (Donohew, Palmgreen, Harrington, and colleagues) in affiliation with the Center. Subsequent studies have demonstrated convincingly that the sensation value of PSAs and the programming context in which these messages are displayed will significantly increase the overall effectiveness of the PSA in changing attitudes toward drugs in high sensation seekers and in reducing drug use by these individuals. Based on this previous work, we have embarked on a new set of experiments conducted in a controlled experimental laboratory (Lynam and colleagues) to determine the mechanism of persuasion by which high sensation value messages influence behavior and if alternative activities or stimulating environments reduce risk-taking among high sensation seekers. We are also beginning work on identifying and developing PSAs and other messages that specifically target other dimensions of personality related to drug use, most specifically low agreeableness and low conscientiousness.
As discussed above, sensation-seeking behavior has been evaluated at a number of complementary levels of analysis. More recently, however, we have recognized that sensation seeking is a multidimensional construct. In the fourth phase of the center, we began to parcel sensation seeking into two separate constructs, namely, reward seeking and inhibition, both of which are biologically-based personality constructs associated with drug abuse and useful constructs for developing targeted drug abuse prevention messages. Bardo and colleagues examined whether these constructs were associated with individual differences in stimulant drug self-administration and mesolimbic neural processes. Kelly’s group conducted parallel studies in humans, examining the role of the constructs of reward seeking and inhibition on drug self-administration and neural activation using fMRI and cortical event-related potential (ERP) methodologies. Lynam, Milich and collaborators initiated a project examining the role of reward seeking and inhibition on the initiation, escalation and cessation of drug use during the transition from adolescence to young adulthood, thus resulting in a synergy across projects.
Progress in our understanding of drug abuse prevention has clearly benefited from interdisciplinary efforts of researchers affiliated with the Center over the years. During the current phase of the Center, we have further expanded our evaluation of the dimensions of impulsivity that are associated with drug abuse vulnerability. A primary focus of the current projects is the four dimensions of impulsivity identified by Lynam and colleagues through factor analytic techniques applied to commonly used impulsivity questionnaires:
(1) Urgency (U), experiencing strong impulses following mood changes;
(2) (Lack of) Premeditation (P), thinking about consequences prior to action;
(3) (Lack of) Perseverance (P), remaining focused on projects and resisting distraction; and
(4) Sensation Seeking (S), enjoyment of exciting and risky activities
The Urgency dimension of the UPPS, in particular, represents a new focus for the Center. Each of the projects will utilize state-of-the-art neuroscience techniques to examine neurobiological mechanisms associated with these personality dimensions. Projects will examine whether these dimensions serve as predictor variables for drug abuse vulnerability outcomes across different samples. The long-term goal of this work is to translate our basic research into the development of more efficacious prevention efforts, and during the current phase of the Center, small-scale ‘proof-of-concept’ prevention trials will be examined as potential incubators of future full-scale prevention interventions.