Which of the following patient characteristics would most strongly suggest that agonist (methadone or buprenorphine) treatment, rather than antagonist (naltrexone), is more likely to be appropriate for medication-assisted treatment (MAT) of opioid use disorder?
1) high motivation for abstinence
2) high need for external structure
3) history of opioid use via non-IV routes only
4) one-year history of opioid use disorder
5) relapse during prior agonist treatment