Effects of naloxone on normals and chronically anxious patients

A significant number of normal and chronically anxious subjects were able to discriminate subjectively between a session in which they received naloxone and one which they received a placebo. However, affective and physiological measures did not differ significantly between the drug and placebo sessions. The weakness of the response makes it unlikely that a naloxone-responsive endogenous opioid system is substantially involved in the regulation of anxiety. An unexpected finding from the placebo session data was that, despite increased forehead muscle tension and high self-ratings of distress, chronically anxious subjects showed consistently stable sympathetic activity under resting conditions and mild stress, indicating the existence of a subgroup of generalized anxiety patients with low autonomic reactivity.