Transcranial direct current stimulation combined with cognitive training improves decision making and executive functions in opioid use disorder: a triple-blind sham-controlled pilot study.

Background: Opioid use disorder (OUD) is a chronic disorder with a considerable amount of morbidity and mortality. Despite remarkable improvement achieved by maintenance programs, an array of treatment goals were still unmet. Mounting evidence suggests that transcranial Direct Current Stimulation (tDCS) improves decision making and cognitive functions in addictive disorders. tDCS paired with a decision making task was depicted to diminish impulsivity as well. Objectives: The present study aimed to assess the effect of tDCS combined with cognitive training (CT) in OUD for the first time. Methods: In this triple-blind randomized sham-controlled pilot study, 38 individuals with OUD from the Buprenorphine-Naloxone Maintenance Therapy program were administered 20-minutes of 2 mA active/sham tDCS over the dorsolateral prefrontal cortex with concomitant cognitive training. A selected test battery evaluating decision making under risk and ambiguity as well as executive functions, verbal fluency and working memory was utilized before and after the intervention. Results: Greater improvements were observed in decision making under ambiguity ( p  = 0.016), set shifting ability and alternating fluency while no improvements were observed in decision making under risk in the active group, compared to sham. Conclusions: Deficits of decision making and executive functions have a pivotal role in the perpetuation and the relapse of the OUD. Alleviation of these impairments brought tDCS/CT forth as an expedient neuroscientifically-grounded treatment option that merits further exploration in OUD, Trial registration: NCT05568251.