Transcranial direct current stimulation in the treatment of alcohol, tobacco and opioid use disorder in clinical studies

Transcranial direct current stimulation (tDCS) is a promising research tool to address substance abuse, including alcohol, tobacco, opioid, and drug use disorders. The present literature review compared previous studies conducted with various current intensities, application regions, durations of stimulations, and different region targets of the brain. Studies based on the analyses conducted after tDCS administration in substance use disorder were promising for the use of tDCS as adjunctive therapy to reduce visible psychological and neurological symptoms of the addiction. Therefore, we aimed to provide an insight into the current state of research on tDCS as a therapeutic intervention in substance use disorders, identify gaps in the literature, and emphasize future investigation areas. Ultimately, the review sought to contribute to the understanding of the role of tDCS in addressing the complex challenges posed by substance use disorder, and its potential as a complementary or adjunctive treatment modality in addiction care. The present study identified that the left dlPFC and brain regions were effective targets for 1 mA and 2 mA tDCS current density in tobacco/nicotine use disorder. Also, the left dlPFC and 2 mA current density were identified as effective targets for tDCS in alcohol use disorder. Furthermore, left dlPFC and 2 mA current density were identified as effective targets for tDCS in opioid use disorder. Additionally, the right/left dlPFC, orbital frontal cortex, thalamus, and 2 mA current density were identified as effective targets for tDCS in other drug or substance use disorders. Animal studies demonstrated that tDCS was promising in reducing neuropathic pain, modulating neuropeptide Y activity, and reducing the redevelopment of ethanol consumption in animal models. However, further research is required to fully understand the optimal tDCS application parameters.