The relationship between executive functioning and substance abuse

Substance use disorders are a widespread issue in society today with approximately 20 million people in the U.S. alone experiencing drug-related problems (Substance Abuse and Mental Health Services Administration, 2012). However, treatment is often ineffectual with approximately 50% o f addicted individuals returning to substance use. One factor found to impact individuals’ treatment response is their neuropsychological functioning. Drug-abusers frequently exhibit severe executive functioning impairments across a number o f domains, and there is evidence that these deficits may be time and substance-dependent. Executive functions are mental processes critical in motivation, planning, and goal-directed behaviors. With extended abstinence, research suggests cognitive improvements will occur for many addicts. The goal o f the present study was to evaluate specific impairments in cognitive abilities and executive functions associated with substance abuse for individuals entering residential treatment and to assess the relationship between self-report executive functioning problems and functioning observed on neuropsychological tests. It was hypothesized that participants would exhibit significant impairments in the areas o f working memory, set-shifting, inhibition, planning, verbal fluency, and sustained attention. Further, it was hypothesized that improvements in executive functioning would be observed after approximately 45 days o f treatment. Moreover, it was hypothesized that executive functioning measures, both self-report and performance-based, would predict substance-related problems, years o f abuse, and problematic personality traits. Finally, better neurocognitive functioning at intake was hypothesized to be related to treatment retention. This study examined adult participants receiving treatment within a private residential addiction center. Findings generally did not provide support for hypotheses. Results found participants reported significant levels o f executive functioning problems but exhibited significantly poorer performance on only one neuropsychological measure (Comprehensive Trail-M aking Task) compared to established norms which indicated deficits in set-shifting ability. Further, significant improvements at follow-up testing were observed in only three executive functioning tasks, although fewer executive functioning problems were reported by participants across multiple domains. It may be that more extensive cognitive improvements were not observed given the generally average performance o f the sample across the neuropsychological battery administered. Further, the only executive functioning measure found to be a significant predictor o f substancerelated problems and problematic personality traits was the self-report Barkley Deficits in Executive Functioning Scales. Finally, scores on initial executive functioning measures were not found to be predictive o f treatment retention. One possible explanation for these results may be the characteristics o f the sample studied as the participants were generally well-educated with likely higher levels o f general cognitive functioning compared to similar research. APPROVAL FOR SCHOLARLY DISSEMINATION The author grants to the Prescott Memorial Library o f Louisiana Tech University the right to reproduce, by appropriate methods, upon request, any or all portions o f this Dissertation. It is understood that "proper request” consists o f the agreement, on the part o f the requesting party, that said reproduction is for his personal use and that subsequent reproduction will not occur without written approval o f the author o f this Dissertation. Further, any portions o f the Dissertation used in books, papers, and other works must be appropriately referenced to this Dissertation. Finally, the author o f this Dissertation reserves the right to publish freely, in the literature, at any time, any or all portions o f this Dissertation.