Longitudinal Neural Fingerprinting of Opioid-use Trajectories

Inclusion Criteria: * within the first 6 months of methadone treatment for OUD and on a stable dose of methadone * eligibility for MRI scanning * willing to commit to longitudinal study visits Exclusion Criteria: * current psychosis, mania, or suicidal ideation with intent, as assessed during screening with the SCID-5 * current co-occurring severe substance-use disorders (excluding nicotine and opioids), as assessed during screening with the SCID-5 * current intoxication or acute withdrawal at time of study visit sufficient to prevent participation based on: behavioral observation, breathalyzer, and SOWS assessment (these individuals will be allowed to enroll at a later date once stable) * severe cognitive impairment (determined through consent process conducted by trained clinical research staff and during consent quiz or as indicated by a PROMIS Cognitive Function t-score \<30 (i.e., score indicating severe impairment) * Past or present history of intellectual disability or developmental disorder * Neurological disease (including seizures or epilepsy) as assessed by self-report and by consulting clinic records * Head trauma with loss of consciousness of more than 30 minutes * Organ dysfunction or any unstable or untreated medical conditions that may alter cerebral function or interfere with study participation