Analysis and modification of opiate reinforcement.

The authors describe a research protocol for the evaluation of narcotic antagonists which examines the heroin-seeking behavior of hard-core heroin addicts on a research ward under blocked and unblocked conditions. Each patient served as his own control. This paper serves as an introduction to a series of papers which follow dealing with behavioral, psychiatric, and aftercare results. It describes detailed methods and preliminary results for the first 21 subjects admitted to the study. More specific results are reported in the papers that follow.