The Comparison of Updating Function of Working Memory in Three Groups of Substance Abusers (Heroin, Opium), Those Treated with Methadone and Normal Controls

Chronic use of opiates is associated with a wide range of neuropsychological deficits. Therefore, this study aimed to evaluate one of the neuropsychological functions, updating function of working memory, in three groups, including substance abusers (heroin and opium), those under treatment with methadone, and normal controls.
The method of this study was causal-comparative. Ninty individuals in three groups, including substance abusers (n = 30), those under treatment with methadone (n = 30), and normal controls (n = 30) were selected from people referred to the addiction treatment Clinics in Shiraz (2015) with the purposeful sampling method. All subjects were evaluated regarding working memory updating and self-reported mental effort scale and the results were analyzed by Multiple Analysis of Variance (MANOVA) test and Tukey post hoc test with SPSS software (version 23).
The results showed a significant difference between the three groups in the updating function of working memory; so that effectiveness and efficiency of processing in the normal group was better than the other two groups and the performance effectiveness and efficiency of processing in the group under methadone treatment was better than substance abusers group.
substance abuse has a negative effect on neurological function. Given that the group of methadone treatment had better performance in the updating function of working memory than the group of substance abusers, these results provide hope that the effects of examined drugs on working memory is not permanent and we can look for psychological interventions to treat these patients and prevent problems recurrence