Research on Substance Abuse

Research Focus

Why does one person in a family develop a drinking problem while other members of the family do not? Why do some adolescents who try alcohol or drugs become dependent on them while others do not? Why do some people develop drug and alcohol problems during adolescence while others develop them late in adulthood? Understanding the psychological, biological, and environmental factors that contribute to the onset and development of substance use disorders is the main focus of our research on substance abuse.

Substance use disorders (e.g., alcohol dependence, drug abuse, etc.) are more common among people with antisocial behavior problems, certain personality features (low constraint and high negative emotionality), deviant peers, and other characteristics associated with impulsivity or deviant behavior. Why is it that these particular characteristics are associated with substance use problems? Our research is guided by the theory that substance use problems are underlied (at least in some people) by deficits in behavioral and cognitive inhibition. That is, people who have difficulty inhibiting impulsive and risky behaviors as well as problems thinking through the consequences of their behavior are at risk for developing substance use problems.

Recent Research Findings

Data collected from a study of psychophysiological (e.g., heart rate and sweat gland activity), emotional, and cognitive functioning as they relate to co-occurrence of substance use problems and certain maladaptive personality features yielded a replication of previous findings and some new insights into factors related to substance abuse. Findings suggested that people who were unable to take advantage of the predictability of an aversive noise thereby reducing its psychological impact were more likely to have alcohol, cannabis, and other illicit drug use problems than people who were able to reduce the impact of the noise when it was made temporally predictable (evidenced by reduced autonomic response to predictable noises). This finding replicated results from an earlier study but the effect was not extended to maladaptive personality features, indicating a potentially specific relation between modulation of autonomic responses and substance abuse.

Leonardo Bobadilla, a graduate student in the lab, found a potentially enlightening finding with regard to the interplay between physiological reactivity to unpredictable aversive noises and subjective perceptions of one's physiological reactivity. Specifically, he found that people who had a mismatch between these two forms of reactivity (e.g., the participant showed high physiological reactivity but reported subjective impressions that he/she had not reacted strongly to the noises) were more likely to have alcohol and cannabis use problems and features of antisocial personality disorder than those showing concordance in these dimensions of reactivity. These findings highlight a possible role for the interplay between cognitive and physiological reactivity in disinhibited psychopathology (e.g., substance abuse).

Current Research

The current focus in our lab is on electrodermal response modulation (ERM) as an endophenotype for substance dependence, particularly illicit drug dependence. We just completed four small studies examining critical features of the Cooltest task used to elicit ERM, which reflects the extent to which people take advantage of the predictability of an aversive stimulus in order to “tune it out.” Through those studies we discovered important roles for attention (mediated via frontal lobe structures) and salience of the stimulus (mediated via limbic system structures). We also examined data from another study and found some initial evidence for associations of ERM with risky variants of dopamine and serotonin receptor genes. Projects are being planned to further examine the relationship of ERM to specific symptoms of drug dependence and to find risky genetic variants associated with ERM.