Association between blood level of plasma oxytocin and novelty seeking among methadone-maintained heroin users

Background: Oxytocin interacts with the dopaminergic system, which plays a role in addiction behaviors. The association between oxytocin and addiction was confirmed in animal studies. Novelty seeking is one of the predictors and indicators of drug addiction. The aim of the present study was to probe the association between oxytocin and novelty seeking. Methods: The study was conducted in a methadone maintenance therapy clinic of a medical center in Taiwan; 77 patients with heroin dependency were enrolled. Plasma oxytocin was measured using an ELISA kit. Novelty seeking was measured using an established instrument (the novelty seeking subscale of the Tridimensional Personality Questionnaire). Results: A significant negative association (ρ = -0.27, p = 0.02; r = -0.34, p = 0.003) between the blood level of plasma oxytocin and novelty seeking was found. This association was significant after controlling the effects of perceived social support and the dosage of methadone (r = -0.32, p = 0.006). Conclusion: The negative association between oxytocin and novelty seeking may provide insight into future treatments for addiction.