Trends of Brain Stimulation Research in Substance Use Disorder: A Review of ClinicalTrials.gov Registered Trials and Their Publications

Abstract

Purpose of the Review: Brain stimulation techniques targeting neuronal pathways are evolving as a novel therapeutic option for substance use disorders. This study aims to provide an overview of the current research landscape on brain stimulation in addiction psychiatry by analyzing data from ClinicalTrials.gov. It intends to describe the global trends in these trials, highlight the findings reported in their publications, and identify the gaps and challenges to guide future research and clinical practice. Collection and Analysis of Data: The ClinicalTrials.gov was searched on March 1, 2024, using every possible paired combination of different brain stimulation techniques (including transcranial magnetic stimulation/TMS, transcranial direct-current stimulation/tDCS, deep brain stimulation/DBS, and vagal nerve stimulation/VNS) and psychoactive substances. A total of 163 human trials were identified, and their details were extracted into a datasheet. Completed and terminated studies were searched separately for publication data. The extracted data were then analyzed using suitable descriptive statistics. Conclusion: Most research involved TMS, tDCS, and DBS and focused on alcohol, stimulants, opioids, nicotine, and cannabis. No studies addressed sedatives, hypnotics, hallucinogens, psychedelics, and solvents. Wide variations in modulation protocols and neuroanatomical targets reflect the current lack of guidelines or consensus. Incompleteness and updating delays in the study registry raise concerns regarding registration protocols. The published trials report beneficial effects of TMS in nicotine, stimulant, and cannabis users, TMS in alcohol users, and VNS in opioid users.