Journal of

Introduction: Chronic drug use has been associated with a wide range of neuropsychological deficits. Therefore, this study aimed to evaluate the performance of the neuropsychological functions among three groups of opioids abusers, treated with methadone and non-user individuals.

Methods: The causal-comparative research method was used in this study. The participants were selected through purposeful sampling method. 90 participants were divided into three groups; opioids abusers (n=30), treated with methadone (n=30) and non-user participants groups (n=30). All subjects were completed the Wisconsin card sorting test and self-reported mental effort scale, and their performance on these tasks was measured and evaluated by both processing efficiency and performance effectiveness. The results were analyzed using one-way ANOVA, Tukey post hoc test and SPSS software (Ver 23).

Results: The results showed that in treated with methadon and opioids abusers groups, in two dimensions of performance effectiveness and efficiency of processing were meaker than the non-user group (p< 0/01). In addition, the performance effectiveness in the group of treated with methadone were better than opioids abusers (fewer preservation error) (p < 0.01).

Conclusion: This result that the treated with methadone participants had better performance effectiveness rather than opioids abusers group could have important implications in pathology and treatment of substance abuse. From this perspective, recognizing the underlying mechanisms that have helped to methadone users for having more effective functions, can be effective in developing of cognitive rehabilitation programs in these patients.