Background and Aim: Substance abuse is one of the chronic psychiatric diseases and results of many studies indicate cognitive dysfunctions associated with it. Using neuromodulation techniques such as transcranial direct current stimulation (tDCS) have demonstrated promising effects in modulating cognitive functions. Therefore, the present study aimed to investigate the effectiveness of tDCS on executive functioning deficits in substance abusers. Methods: This research was a quasi-experimental study with experimental and control groups. Its statistical population included those who referred to one of the addiction treatment centers located in the north of Tehran. A group of 10 individuals voluntarily participated in this research (5 in the experimental and 5 in the control group). Both groups responded to Barkley deficits in executive functioning scale (BDEFS for Adults). The tDCS applied over the dorsolateral prefrontal cortex (DLPFC) (anodal stimulation of F3 region, and cathodal stimulation of F4 region with a current start of 2 mA) for 5 weeks and 3 sessions every week, only the experimental group received this treatment. Results: The results of multivariate analysis of variance (MANOVA) showed significant differences between two groups in Self-Management to Time, Self-Organization/Problem Solving, Self-Motivation, and Self-Regulation of Emotion, but not in Self-Restraint. In over all, the experimental group had lower scores in the executive dysfunction questionnaire (p<0.5). Conclusion: It could be said that tDCS has an effect on improving the executive functions in daily life in substance abusers.
