Psychopharmacological Effects of Oxycodone in Volunteers With and Without Generalized Anxiety Disorder

A number of studies have documented a relationship between anxiety disorders and opioid misuse and abuse, and there is some data to suggest that some people use opioids in an attempt to reduce their anxiety. We tested the hypothesis that volunteers with an anxiety disorder would report a more positive spectrum of subjective effects (i.e., greater ratings of drug liking and wanting to take the drug again) from oxycodone, a mu opioid agonist, than would volunteers without the disorder, and that oxycodone would have greater reinforcing efficacy in volunteers with the anxiety disorder. In addition to subjective and reinforcing effects, the psychomotor and physiological effects of oxycodone also were assessed. Individuals with generalized anxiety disorder (GAD, n = 8) and nonanxious controls (CTL, n = 8) were administered 0, 10, and 20 mg oxycodone (per os) in 3 separate sessions. Oxycodone produced a number of effects in a dose-related fashion in both groups. However, on several subjective effects measures, only CTL participants reported effects of oxycodone (e.g., high, lightheaded). Neither group had statistically significant increases ill peak liking or "take drug again" ratings in the oxycodone conditions relative to the placebo condition, and in neither group did the drug function as a reinforcer, as measured by the Multiple-Choice Procedure (Griffiths, Troisi, Silverman, & Mumford, 1993). Anxiety ratings were low in the GAD group (in the absence of drug), and this may have lessened the possibility of detecting a more positive spectrum of oxycodone effects in this group than in the CTL group.