Transcranial Direct Current Stimulation (tDCS) paired with a decision-making task reduces risk-taking in a clinically impulsive sample

Background: Impulsivity is a multidimensional personality trait observed across a variety of psychiatric disorders. Transcranial direct current stimulation (tDCS) applied over dorsolateral prefrontal cortex (DLPFC) has shown promise as an intervention to reduce impulsivity. Objective: To investigate the effects of tDCS paired with a decision-making task on risk-taking in Veterans with a clinical history of impulsive behavior. Methods: This was a randomized, single-blind, sham-controlled study. Participants performed the Balloon Analogue Risk Task (BART) while concurrently receiving either active or sham tDCS (right anodal/left cathodal over DLPFC) twice a day for five days. To evaluate generalization, the Risk Task was performed before and after the complete course of intervention. To evaluate durability, the BART and Risk Task were administered again at one and two month follow-up sessions. Results: Thirty Veterans participated: 15 received active tDCS and 15 received sham tDCS. For the trained BART task, individual growth curve analysis (IGC) examining individual variation of the growth rates over time showed no significant variations in individual trajectory changes over time (β = 0.02, p > 0.05). For the untrained Risk Task, IGC showed that the active tDCS group had a significant 46% decrease in risky choice from pre-to post-intervention, which persisted through the one and two month follow-up sessions. The sham tDCS group showed no significant change in risky choice from pre-to post-intervention. Conclusions: tDCS over DLPFC paired with a decision-making task effectively reduced risk-taking behavior in a group of Veterans with clinically-relevant impulsivity. Results suggest that this approach may be an effective neuroplasticity-based intervention for patients affected by impulsivity.