2.1. Ethics statement
DISORDER
This study was approved by the Western Institutional Review Board (WIRB Protocol #20171742, Transcranial Direct Current Stimulation to Modulate Top-Down Regulation for Drug Craving in Methamphetamine Use Disorder [NeuroMethDC]). The research adhered to the principles of the Declaration of Helsinki and was conducted in compliance with relevant guidelines and regulations. Formal written consent was obtained from all participants before any procedures took place. All participants were adults; thus, no parental or guardian consent was required.