Synergistic effect of combined transcranial direct current stimulation and Matrix ‎Model on the reduction of methamphetamine craving and improvement of cognitive ‎functioning: a randomized sham-controlled study

Background: Addiction is associated with decreased activity of the prefrontal networks, especially dorsolateral prefrontal cortex (DLPFC).Objective: This study examined the effectiveness of transcranial direct current stimulation (tDCS) over DLPFC in combination with Matrix Model psychotherapy in the alleviation of craving and cognitive improvement of participants with methamphetamine use disorder.Methods: In a randomized and sham-controlled trial, 60 male participants were assigned to Matrix psychotherapy only, sham tDCS plus Matrix, or active tDCS plus Matrix. Sixteen sessions of 20-min anodal (2 mA over F3 for targeting the left DLPFC) or sham tDCS along were administered in the outpatient setting. Pre- and post-intervention craving, executive functioning, and working memory were assessed using the Obsessive-Compulsive Drug Use Scale, Wisconsin Card Sorting Test, and Wechsler Memory Scale, respectively. One month following the interventions relapse was investigated by urine drug screen or interview.Results: In comparison with sham tDCS (n = 12) and Matrix psychotherapy only group (n = 13), the active tDCS group (n = 15) showed more reduction in craving (p<.05, η2 = .21). Auditory and visual memory (Wechsler) and true answers and false answers (WCST) significantly improved in the active tDCS group (η2 = .18, η2 = 12, η2 = 03, η2 = .02, respectively) but not in the other groups. Relapse rates did not significantly differ between groups (p = .17). A significant correlation was found between craving reduction and cognitive functioning in the active tDCS group.Conclusion: The combination of Matrix Model psychotherapy and tDCS may an effective therapy for cognitive improvement and craving in participants with methamphetamine use disorder.Clinical Trials Registry: This study was registered at the Iranian Registry of Clinical Trials (IRCT20161026030510N3).