Measuring Acute Drug Demand in Humans

This research is being done to evaluate whether suvorexant may reduce the use of, subjective liking, and demand for various drugs.

Inclusion Criteria: * Age between 18 and 65 years old * Meets Diagnostic and Statistical Manual-5 criteria for Opioid Use Disorder (OUD) (moderate or severe) * Lifetime substance use history criterion \[blinded\] * Medically cleared to take suvorexant and blinded study medications * Be in good general health based on a physical examination, medical history, vital signs, and screening urine and blood tests Exclusion Criteria: * Pregnant or breast feeding * Seeking opioid use treatment * Significant mental health or physical disorder that is expected to interfere with study participation as assessed by the study physicians or medical staff * Known contraindications or allergies to suvorexant and/or the blinded study medications