Opioid/Benzodiazepine Polydrug Abuse: Aim 3

Inclusion Criteria:

* must self-report past 10-year experience taking opioid and sedative drugs (for therapeutic or non-therapeutic reasons), but not necessarily at the same time. As an alternative to the sedative drug exposure requirement, participants must have used alcohol on at least 3 separate days during the past month. Participants may have current mild- or moderate-severity Opioid Use Disorder or current mild- or moderate-severity Sedative Use Disorder;
* must not be seeking treatment for their substance use problems;
* must be in current good overall health

Exclusion Criteria:

* meet DSM-5 criteria for current psychosis, bipolar disorder, or severe depression (i.e. severe psychiatric disorder);
* meet DSM-5 criteria for severe substance use disorder for any substance (e.g. Sedative, Opioid, Alcohol);
* past-month benzodiazepine or opioid prescription (which would suggest daily use, tolerance, or withdrawal upon cessation);
* report of past-year any-drug overdose or suicide attempt/ideation;
* exhibit cognitive impairment (IQ \< 80 on the Shipley Institute of Living Scale);
* neurological, cardiovascular, pulmonary, or systemic diseases (see specific exclusionary conditions under Protection of Human Subjects);
* body mass index \> 38 kg/m2;
* females who are pregnant (urine), lactating or heterosexually active (self-report) and not using medically approved birth control;
* treatment with methadone, buprenorphine or naltrexone;
* past 30-day use of contraindicated medications;
* alcohol-positive breath sample (\>.02% breath alcohol concentration);
* urine sample positive for methadone, cocaine, amphetamines, or barbiturates (\<300 ng/ml)
* intolerance of lactose