Impulsivity as a moderator of the intention-behavior relationship for illicit drug use in patients undergoing treatment.

INTRODUCTION: Evident across clinical practice and clinical trials is a divergence between stated intentions and subsequent drug-related behaviors in substance abuse treatment settings. Impulsivity, itself related to drug abuse, may be one variable which may moderate the degree of disconnect in the intention-behavior relationship. The present study examines the relationship between self-stated desire to quit, impulsivity, and drug use in a group of outpatients receiving methadone maintenance treatment. In particular, we examined the direct and moderating influence of different facets of impulsivity (urgency, lack of premeditation, sensation seeking, and lack of perseverance) on drug use in the context of a stated desire to abstain from drugs.

METHOD: 84 opioid-dependent individuals undergoing counseling and methadone maintenance treatment completed a battery of self-report questionnaires including measures of impulsivity (UPPS Impulsivity Scale), stated desire to quit, and past 30-day drug use. We hypothesized that two facets of impulsivity, urgency and (lack of) premeditation, would moderate the relationship between desire to quit and past 30-day drug use, such that the relationship between intention and behavior would be weaker in those with high levels of these facets of impulsivity.

RESULTS: Consistent with the disconnect between intentions and drug-use behaviors typical of treatment settings, desire to quit was not directly associated with self-reported past month drug use. However, in separate regression analyses, 2 facets of impulsivity, premeditation and sensation seeking, moderated the relationship between desire to quit and past month use. Whereas there was not a significant relationship between desire to quit and drug use in individuals high in sensation-seeking or lack of premeditation, the relationship between intention and drug use behaviors was preserved in those low in these facets of impulsivity.

CONCLUSION: These findings indicate that the relationship between desire to quit and self-reported past-month drug use is weak for those high in sensation seeking or low in premeditation. These results are discussed in the context of current interventions for substance dependence.