Some research suggests that administration of oxytocin with oxycodone may reduce its abuse liability and improve its ability to reduce pain. In a 6-session laboratory study, the investigators will be evaluating the effects of oxycodone and oxytocin (combined and separately, across sessions) on experimentally-induced pain, subjective effects, decision-making, and activation of different neural substrates.

The overall project goals are to determine oxytocin effects on oxycodone's subject-rated abuse liability, experimental pain, and to describe the neurobehavioral mechanisms underlying interindividual differences in these effects. Generally healthy individuals (determined via medical history review and a screening session) will, after informed consent, self-administer intranasal oxytocin (or placebo, containing the same ingredients but no oxytocin) shortly after oral oxycodone or placebo in a non-residential, double-blind, randomized, placebo-controlled, within-subjects laboratory study. Prescreening will assure MRI eligibility and drug application safety and, using a validated, comprehensive pain history interview, determine previous or existing chronic pain conditions, including current pain medication use.

Inclusion Criteria:

• Individuals fluent in English will participate.
• Must report recreational use of opioids.
• Be within 20% of their ideal body weight.
• Are not currently experiencing chronic pain (pain on most days during the past 3 months)
• Have a systolic blood pressure of <=140 and diastolic blood pressure of <= 90, and a heart rate <= 90 beats per minute.
• Participants must also have a normal electrocardiogram (EKG) reading and bloodwork indicating no major health contraindications.

Exclusion criteria:

• Significant current physical disease or major psychiatric disorder.
• No self-reported current interest in drug abuse treatment.
• Women who are pregnant or nursing.
• Any comorbid illicit substance use disorders or current clinically significant withdrawal for any abused drug excluding nicotine and caffeine.
• Any conditions that preclude safety in the MRI scanner, such as: implanted electrical devices (e.g., cardiac pacemaker, neurostimulator); implanted metallic clips or pins (e.g., aneurysm clip); a history of working with metal (unless able to demonstrate participant is MRI safe), and claustrophobia.