Serum Level of GDNF is Associated with Adherence to Methadone Maintenance Treatment

Background: Preclinical studies have shown that neurotrophic factors, including brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), are involved in the modulation of biochemical and behavioral adaptations to substance use. Methods: We studied the impact of GDNF and BDNF serum levels on adherence to methadone maintenance treatment (MMT) through cross-sectional research. Participants were clients on MMT (43 males), subjects in remission from opioid use disorder (12 males), and healthy controls (20 males). Adherence and non-adherence to treatment were assessed by the detection of illicit opioids in random urinalysis. Results: Using t-tests for independent groups and analysis of variance (ANOVA), GDNF serum levels in the adherent patients to MMT were found to be significantly higher than in the non-adherent patients. BDNF serum levels were not different between adherent and non-adherent patients. Conclusions: Our results suggest the involvement of GDNF as a biological factor in adherence to MMT.