A Randomized Placebo-Controlled Trial of Targeted Prefrontal Cortex Modulation with Bilateral tDCS in Patients with Crack-Cocaine Dependence

Background: Transcranial direct current stimulation over the dorsolateral prefrontal cortex has been shown to be clinically useful in the treatment of drug addiction. Methods: We conducted a double-blind randomized clinical trial aiming to assess the effects of bilateral dorsolateral prefrontal cortex transcranial direct current stimulation (left cathodal/right anodal) on crack-cocaine addiction. We defined craving as the primary outcome, and other clinical measurements, including depressive and anxiety symtoms, and quality of life, as secondary outcomes. Seventeen male crack-cocaine users (mean age 30.4 +/- 9.8 SD) were randomized to receive 5 sessions of active transcranial direct current stimulation (2 mA, 35 cm(2), for 20 minutes), every other day, and 19 males (mean age 30.3 +/- 8.4 SD) to receive sham-transcranial direct current stimulation (placebo) as control group. Results: Craving scores were significantly reduced in the transcranial direct current stimulation group after treatment when compared with sham-transcranial direct current stimulation (P =.028) and baseline values (P =.003), and decreased linearly over 4 weeks (before, during, and after treatment) in the transcranial direct current stimulation group only (P =.047). Changes of anxiety scores towards increase in the sham-transcranial direct current stimulation and decrease in the transcranial direct current stimulation group (P =.03), and of the overall perception of quality of life (P =.031) and of health (P =.048) towards decrease in the sham-transcranial direct current stimulation group and increase in the transcranial direct current stimulation group differed significantly between groups. Conclusions: Repetitive bilateral transcranial direct current stimulation over the dorsolateral prefrontal cortex reduced craving for crack-cocaine use, decreased anxiety, and improved quality of life. We hypothesize that transcranial direct current stimulation effects may be associated with increased prefrontal processing and regulation of craving behavior.