Modeling variability in tDCS-induced electric fields in depression: age-related comparisons in stratified adolescent and adult samples

Transcranial direct current stimulation (tDCS) has emerged as a safe, cost-effective, and scalable therapeutic strategy, with moderate effects for depression in adult patients. However, there are no published studies on tDCS in children and adolescents with depression. This study is the first to investigate the simulated regional electric fields (EF) in adolescents at risk for or currently experiencing depression. A total of 150 Brazilian adolescents (50 at low risk, 50 at high risk of developing depression, and 50 diagnosed with depression) were drawn from the Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo) and compared to 51 adults with depression. Employing a tDCS protocol designed for adults, we measured the simulated EF magnitude in the bilateral dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), both key brain areas involved in depression. Statistically significant differences in EF magnitudes were observed between each adolescent group (low risk, high risk, and diagnosed with depression) and adults with depression, while no significant differences were found among the adolescent groups themselves. By focusing on a population that is often underrepresented in depression research, this study may pave the way for future trials to treat depressive disorder in adolescents with tDCS.