Endogenous opiate system and systematic desensitization.

In a double-blind study, phobic patients received intravenous infusions of either naloxone or saline prior to systematic desensitization. Saline-infused subjects significantly demonstrated the predicted symptoms decrease in response to systematic desensitization, whereas naloxone-infused subjects showed no change. Subject reports and psychophysiological measures of arousal indicated no discriminable awareness of the naloxone versus saline condition. The findings appear to be consistent with the hypothesis that activation of the endogenous opiate system (EOS) plays a role in the effectiveness of systematic desensitization. Implications for a common mechanism underlying behavioral and pharmacological treatments are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)