Human drug abuse liability assessment: opioids and analgesics.

Methods are described for assessment of the abuse liability of opioids and analgesics. The methods developed by the USPHS Addiction Research Center for assessment of opioid abuse liability have served as the prototype for most currently used abuse liability assessment approaches. The general method is that of comparing the profile of effects of a test drug to the profiles of placebo and of a known drug of abuse. Drugs with profiles of activity similar to the known drug of abuse are considered pharmacologically equivalent and of similar abuse liability. Specific methods, including the Addiction Research Inventory, adjective- and visual analog rating scales, are described, as are methodological developments that have been introduced to improve the sensitivity of the procedures and to adapt them to modern circumstances. It is concluded that the profile-of-effects methodology has proven extremely useful and should remain a basic element in abuse liability assessments.