The quantitative assessment of physical dependence on opiates.

A procedure for administering naloxone to narcotic-dependent individuals and a technique for quantitating the ensuing acute withdrawal syndrome have been developed to assess the degree of physical dependence. Successive injections of increasing doses of naloxone produce a controlled increase in severity of withdrawal signs and symptoms as measured by a subjective and an objective assessment battery. There is good agreement between the subjective and objective assessments and a global reting of withdrawal severity. The objective measures are, however, most sensitive and produce a withdrawal syndrome score related to the duration of the current cycle of drug abuse. Hand tremor, trapezius electromyogram and heart rate are the most sensitive signs of withdrawal and can be used in combination to form the basis of a simplified and shortened antagonist assessment test for physical dependence.