Effect of Transcranial Direct Current Stimulation on Craving, Cognitive Functions, and Serum Brain-Derived Neurotrophic Factor Level in Individuals on Maintenance Treatment for Opioid Use Disorder, A Randomized Sham-Controlled Trial

Objectives To investigate the effects of transcranial direct current stimulation (tDCS) on brain-derived neurotrophic factor (BDNF) levels, craving, and executive functions in individuals on maintenance treatment for opioid use. Methods We randomized 70 right-handed men aged 18–55 years into 2 groups: the intervention group and the sham group. The intervention was 10 sessions of 2 mA stimulation over 5 days. Each session in the sham group ended after 30 seconds. Craving was measured using the Desire for Drug Questionnaire (DDQ), Obsessive Compulsive Drug Use Scale (OCDUS), and visual analog scale (VAS). The measurements were taken before and after the intervention, as well as 2 months later. BDNF was measured before and after the intervention. Repeated-measures analysis of variance, the generalized estimating equation model, and independent t test were used for data analysis. Results The mean differences (95% confidence intervals) in pre and post craving scores in the intervention group were (12.71 9.10 to 16.32, P = 0.167) for VAS, (1.54 1.12 to 1.96, P = 0.012) for OCDUS, and (1.71 1.27 to 2.15, P = 0.125) for DDQ. These measures in the control group were −0.44 (−1.19 to 0.30), 0.01 (−0.21 to 0.23), and 0.126 (−0.11 to 0.36), respectively. BDNF serum levels significantly increased after the intervention (difference, 0.84 0.69 to 0.99, P < 0.001); however, this change was not significant in the generalized estimating equation model. The effect of tDCS on craving was significant in OCDUS, but not significant in VAS and DDQ. Conclusions The tDCS reduces craving and improves executive functions in the short term. BDNF serum level was not associated with tDCS.