The Association between the Level of Plasma Oxytocin and Craving among Former Heroin Users

Abstract

BACKGROUND: Animal studies have demonstrated that oxytocin can influence addiction behaviors and might interact with the dopaminergic system, which is a key component of addiction behaviors. However, related evidence from clinical studies is scarce. The aim of our study was to explore the relationship between plasma oxytocin level and heroin craving among patients receiving methadone maintenance treatment, and to ascertain whether this relationship is moderated by novelty-seeking. METHODS: The study was conducted in a methadone maintenance therapy clinic of a medical center in Taiwan. Seventy-seven patients with heroin addiction were enrolled. Plasma oxytocin was measured using an ELISA kit. Craving was assessed using an established instrument, the Chinese Craving Scale. RESULTS: A significant negative association was found between the plasma oxytocin level and craving score, which remained robust after controlling the effects of social support and low-density lipoprotein cholesterol. An interaction between oxytocin and novelty-seeking indicated that this relationship was stronger among patients with a lower level of novelty-seeking. CONCLUSION: This finding may be taken into account in future studies and may provide a basis for the development of potential treatment for addiction. The effect of oxytocin for the treatment of opioid dependence might be modulated by some psychological factors.