Background Negative emotional states and abnormal stress reactivity are central
components in drug addiction. The brain stress system in the amygdala is thought to play a
key role in the maintenance of drug dependence through negative reinforcement. Although
acute heroin administration was found to reduce anxiety, craving, and stress hormone
release, whether these effects are reflected in amygdala activity has not yet been
investigated. Methods With a randomized, crossover, double-blind design, saline and heroin …