Assessment of Executive Functions in Methamphetamine-addicted Individuals: Emphasis on Duration of Addiction and Abstinence

INTRODUCTION Several studies have conducted on impairments of executive functions in individuals with methamphetamine addiction; however, only a few have investigated the relationship between executive functions and duration of addiction or abstinence. This study was designed to assess the executive functions in methamphetamine-addicted individuals in relation to the duration of addiction or abstinence. METHODS A total of 161 subjects aged between 20 and 45 years were categorized into three subgroups: currently abusing (n=41), abstinent (n=60), and control healthy individuals (n=60). A battery of standardized executive function tasks, including Stroop test, Wisconsin Card Sorting test, and Tower of London task, were administered. Data were analyzed using Pearson correlation coefficient, analysis of variance, and post hoc Bonferroni test with SPSS16.0. RESULTS Methamphetamine-addicted and abstinent subjects performed worse than the controls. Methamphetamine-abstinent subjects performed better than the currently methamphetamine abusers in most executive functions. Duration of addiction and abstinence were correlated with executive dysfunctions. CONCLUSION This study revealed that although executive functions may be improved by protracted abstinence, executive dysfunctions are not completely relieved, and specific attention to planning and implementation of intervention programs are necessary.