Administration, Oral Adult Article Buprenorphine Drug Administration Schedule Drug Implants Female Heroin Humans Injections Logistic Models Male Narcotic Antagonists Opiate Substitution Treatment Opioid agonist treatment Opioid-Related Disorders Opioids Patient Preference Substance Withdrawal Syndrome Tablets Young Adult adult affect/emotions buprenorphine buprenorphine plus naloxone chronic illness/stress clinical trial comparative study drug abuse drug administration