The impact exerted by the severity of recreational drug abuse on the different components of the executive function

A number of neuropsychological studies have shown the relationship between severity of drug abuse and the executive functioning of substance abusers, along with its negative impact on treatment results. The aim of this study is to examine the relationship between severity of consumption of alcohol, cannabis, cocaine, heroin, amphetamines and ecstasy on the executive processes of fluency, working memory, response inhibition, concept formation and decision-making. Forty poly-substance abusers participated in this study. In a series of setwise regression analyses we introduced the standardized scores of a severity index as predictor variables, and the raw scores of five indexes sensitive to executive functioning as dependent variables: the Ruff Figural Fluency Test (RFFT), the Letter Number Sequencing subtest (LyN), the 5 Digit Test (5DT), the Category Test (TC) and the Gambling Task (GT). Best subsets of predictors for each dependent variable were included in multiple regression models. We obtained significant relationships between severity of heroin and ecstasy abuse and RFFT performance; between severity of alcohol, cocaine, heroin and amphetamines and LyN performance; between severity of alcohol, cannabis, cocaine, heroin and ecstasy and 5DT performance; and between severity of heroin and amphetamines and TC performance. These results show the significant influence of severity of drug abuse on executive impairment, which may have a negative impact on treatment results.