| With the increasing severity of drug dependence, it brings negative consequence in neural system, cognitive functions and social functions. Thus, acknowledge of underlying mechanism and analysis of potential impairment become the effective paths to comprehend addictive behaviors. During the process of drug abstinence, people need to pay much more efforts in overcoming addictive impulsivity. It highlights the executive functions in the condition of resisting strong habitual responses and temptation. Therefore, this study focused on the characteristics and impairments of executive functions of drug abusers, and then tried to understand the underlying mechanism of addictive behaviors.Although there are massive theories and models of executive function, this study is mainly involved in inhibition, attention and working memory. In details, this study aimed at:(1) adopting stop signal task to explore the impairments in inhibition for drug abusers by comparing the performance in both drug abusers and control people; (2) employing the visual orienting task to investigate the process of covert and overt attention orienting; (3) using digit span and semantic span tasks to evaluate the short time memory, digit working memory and semantic working memory. In addition, this study also tried to analyze the differences in impairments of executive functions between different kinds of drug abusers and between males and females.The addictive participants were recruited from correctional-based drug intervention rehabilitation cooperated by legal system. The control people were recruited according to the characteristics of age, gender and educational levels of experimental group.This study indicated that:(1) compared to the control, drug-dependent people had impaired inhibitory ability. Male drug abusers showed deficits in all inhibitive tasks and female drug abusers showed impairments in high-demanded inhibitive tasks. Among three kinds of drug abusers, the inhibition in psycho-stimulant abusers was most severe impaired, followed by heroin abusers and polysubstance abusers which the two group had the similar degree of deficits. (2) in contrast to control people, addictive people had significant impairments in alertness, especially for female abusers in which group the clues inhibited attention instead of promotion, rather than sustained attention and selective attention. For three kinds of drug abusers, both heroin-dependent and polysubstance-dependent individuals deteriorated in attention-clued alertness task whereas psycho-stimulant abusers had comparatively superior performance than the other addictive groups but still inferior to the control. Although drug abusers showed impairments in both covert and overt attention orienting process, it suggested a gender difference that male abusers had deficits in covert attention orienting and female abusers had impairments in overt attention orienting. (3) drug abusers had impaired digit short memory and semantic working memory contrary to control individuals. Specifically, male abusers had worse performance in digit short memory and semantic working memory than male control people, whereas surprisingly female abusers had better performance in digit short memory than female control people. For three kinds of drug abusers, drug dependence brought most serious damage into heroin addictive people. (4) For the three sub-components of executive functions, the analysis of effect size illustrated that the impairment in working memory is outstanding, whereas the performance in more basic processing (i.e. inhibition and attention) was relatively impaired less than that in working memory.Moreover, the stop signal task, especially longer delayed stop signal task, and semantic working memory were most sensitive to the discrimination of cognitive functions between addictive people and control people and also different types of drug-dependent individuals. The results of this study could be used in further intervention and treatment of addictive behaviors.
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