Rationale: Subjective craving, which contributes to the continuation of drug use in active abuser and the occurrence of relapse in detoxified abusers, is considered to be a central phenomenon in addiction. Dopamine pathway has been implicated in the mechanism underlying the cue-elicited craving for a variety of addictive substances.
Objectives: The objective of this study was to test the hypothesis that heroin addicts carrying D4 dopamine receptor gene (DRD4) variable number tandem repeat (VNTR) long type allele would have higher craving after exposure to a heroin-related cue.
Materials and methods: Craving was induced by a series of exposure to neutral and heroin-related cue and were assessed in a cohort of Chinese heroin abusers (n=420) recruited from the Voluntary Drug Dependence Treatment Center at Shanghai.
Results: Significantly stronger cue-elicited heroin craving was found in individuals carrying DRD4 VNTR long type allele than the non-carriers (F=31.040, p<0.001). As for baseline craving and mean change in craving responding to neutral stimuli, no significance was found (1.06+/-0.34 vs 1.07+/-0.36, F=0.067, p=0.797 and 0.42+/-0.34 vs 0.45+/-0.37, F=0.277, p=0.599, respectively).
Conclusions: The results of our study suggest that DRD4 VNTR polymorphism contributes to cue-elicited craving in heroin dependence, indicating DRD4 VNTR represents one of potential genetic risk factors for cue-induced craving.