The treatment of substance abuse has traditionally focused on the compulsive aspects of the disorder in which craving plays a central role (Mathew, Claghorn, & Largen, 1979). Recently, there has been an increased interest in the role of impulsivity in substance abuse. In this model of substance abuse, at least some drug use does not occur in response to chronic craving, but in a rapid, unplanned fashion. As reviewed in Brady, Myrick, and McElroy (1998), there is evidence for an association between impulsivity and substance abuse. Impulsive populations including individuals with intermittent explosive disorder (McElroy, Soutullo, Beckman, Taylor, & Keck, 1998), impulsive arsonists (Virkkunen, De Jong, Bartko, & Linnoila, 1989), and impulsively violent offenders (Linnoila, 1983) all have higher rates of substance abuse or dependence than the general population.
Studies that have examined children at risk for substance abuse have also found higher rates of impulsivity. Using a model of behavioral self-regulation involving inattention, impulsivity/hyperactivity, and aggression, Dawes, Tarter, and Kirisci (1997) compared children with a family history of substance abuse to those without this history, and found that children with a family history of substance abuse scored higher on the behavioral self-regulation measures (which equated to higher impulsivity). Self-regulation of goal directed behavior was more impaired in another study comparing high-risk children to low risk children, and this measure predicted impulsive aggression in the high-risk group (Giancola, Moss, Martin, Kirisci, & Tarter, 1996).
Most studies objectively measuring impulsivity find higher impulsivity scale scores in substance dependent individuals.
Using the Barratt Impulsiveness Scale (BIS-11), two studies found that substance dependent individuals have higher total scores than controls Allen et al., 1998 and Patton et al., 1995.
However, one study of alcoholic subjects with impulse control disorders did not find increased total BIS scores compared to controls (Lejoyeux, Feuche, Loi, Solomon, & Ades, 1998). In a study using the Eysenck Personality Inventory, drug-abusing patients were less sociable and more impulsive than controls (King, Jones, Scheuer, Curtis, & Zarcone, 1990). Another study using the Psychopathic States Inventory showed higher impulsivity in antisocial substance dependent subjects than controls (Moss, Yao, & Panzak, 1990).
A few studies have attempted to determine the impact of impulsivity on severity or mechanisms of substance abuse. Impulsivity as measured by the BIS-11 was positively correlated with the history of frequency of alcohol consumption in incarcerated individuals in one study (Fishbein & Reuland, 1994). In a second study, impulsivity as measured by the Impulsivity-Venturesomeness-Empathy scale was significantly correlated with self reported euphoria after intravenous cocaine administration (Cascella et al., 1994), implying that more impulsive cocaine-dependent individuals may be biologically at a greater risk for relapse.
Thus, there is evidence of an association between impulsivity and substance abuse from a number of studies examining the issue from several perspectives. In order to determine the relationship between impulsivity and severity of cocaine dependence, a group of 50 cocaine dependent subjects completed the Barratt Impulsiveness Scale (BIS-11), along with measures of quantity of cocaine use, craving and withdrawal. The hypothesis was that there would be a positive correlation between severity of cocaine use and impulsivity.
In order to determine the impact of impulsivity on treatment for cocaine dependence, a subset of 41 subjects entered a 12-week treatment study in which baseline impulsivity was used as a predictor of subject dropout. It was hypothesized that subjects with higher baseline impulsivity would drop out of treatment significantly sooner than would subjects with lower impulsivity.
