Meta-analysis of cue-reactivity in addiction research

Aims. The cue-reactivity procedure exposes addicts to a variety of drug-related stimuli while self-report of craving and physiological responses are monitored. The present review sought to determine the magnitude and overall pattern of responses typically found in cue-reactivity, research and which, if any, learning-based model of cue reactivity is best supported by the findings. Design. Meta-analytical techniques were used to select and evaluate results from 41 cue-reactivity studies that compared responses of alcoholics, cigarette smokers, cocaine addicts or heroin addicts to drug-related versus neutral stimuli. Effect sizes were calculated, separately by addict type, for self-report of craving and physiological responses (heart rate, sweat gland activity and skin temperature). Findings. Across all addict groups, the effect size for craving was +0.92. Alcoholics had a significantly smaller craving effect size (+0.53) compared to other addict groups (+1.18 to +1.29). Relatively smaller effect sizes were found for physiological responses. The general profile of effect sizes across all addict groups was increased heart rate (+0.26) and sweat gland activity (+0.40) and decreased skin temperature (-0.24) when addicts were presented with drug-related stimuli. Conclusions. The cue-reactivity paradigm can produce a stable profile of significant effects and, therefore, has a number of potential applications for investigating addictive phenomena. The implications of these findings for conditioning-based models of cue-reactivity phenomena are discussed.