The effect of bilateral tDCS over dorsolateral prefrontal cortex on the cognitive abilities of men with opioid use disorder under methadone therapy: A sham-controlled clinical trial

Abstract

Abstract Background/aim Opioid use disorder (OUD) can have negative impact on cognitive functions. This study aims to evaluate the effect of bilateral transcranial direct-current stimulation (tDCS) over the right/left dorsolateral prefrontal cortex (DLPFC) on the cognitive abilities of OUD men. Methods This study is a double-blind sham-controlled randomized clinical trial with a pretest/posttest design. Participants were 31 men with OUD living in Zanjan, Iran, assigned to three groups of left anode/right cathode tDCS, right anode/left cathode tDCS, and sham tDCS. The two active groups received tDCS (2 mA) at 10 sessions each for 10–20 min. The Cognitive Abilities Questionnaire (CAQ) in Persian was used to measure their cognitive abilities before and after intervention. Collected data were analyzed in SPSS v.22 software. Results Bilateral DLPFC stimulation resulted in a significant improvement in cognitive flexibility, planning, decision making, inhibitory control/selective attention, and memory of patients in the two active tDCS groups, while the sham tDCS had no significant effect on their cognitive abilities. Conclusion Bilateral tDCS over DLPFC, as an effective and complementary treatment, can improve the cognitive abilities of men with OUD. Trial registration: This study is a double-blind sham-controlled clinical trial (Parallel, IRCT20170513033946N5. Registered 19 Jan 2019, https://en.irct.ir/trial/36081 ).

Keywords

• Transcranial Direct-Current Stimulation
• Dorsolateral prefrontal cortex
• Cognitive function
• Opioid use