Combined tDCS and Cognitive Training as an Adjunctive Treatment in Opioid Use Disorder

Inclusion Criteria: * Ability to provide consent and comply with study procedures * Diagnostic and Statistical Manual of Mental Disorders criteria for OUD * Undergoing medication treatment for OUD. Participants may have current comorbid drug use, but primary diagnosis must be OUD * Intention to remain in the study until intervention completion. Exclusion Criteria: * Any medical condition with neurological sequelae * Head injury resulting in skull fracture or loss of consciousness of \>30 minutes * Any tDCS or MRI contraindication (tDCS: history of seizures, metallic cranial plates/screws or implanted device, history of eczema on scalp. MRI: unapproved metallic implants, pacemakers or any other implanted electrical device, shrapnel, metallic braces, non-removable body piercings, pregnancy, breathing or movement disorder, or claustrophobia) * Any psychotic disorder (participants with other treated and stable psychiatric disorders will be included) * Presence of a condition that would render study measures impossible to administer or interpret * Age younger than 18 * Primary current substance use disorder on a substance other than opioids except for caffeine or nicotine * In treatment instead of jail * Pregnancy * Disrespectful behavior towards the investigators and staff.