Home-Based tDCS for Depression in BPD

Background Major Depressive Disorder (MDD) is the most common comorbidity among individuals with Borderline Personality Disorder (BPD), affecting over 85% of patients and leading to high recurrence rates and resistance to treatment. Traditional pharmacological and psychotherapeutic interventions often show limited efficacy in this population, highlighting the need for innovative treatment strategies. Emerging evidence suggests that the dorsolateral prefrontal cortex (DLPFC) plays a crucial role in the pathophysiology of both MDD and BPD. In addition, non-invasive brain stimulation, particularly transcranial Direct Current Stimulation (tDCS), has shown promising results in alleviating depression and improving BPD symptoms when targeting the DLPFC. The development of home-based tDCS presents new opportunities for accessible and cost-effective interventions. However, no study has specifically investigated its effects on MDD in the context of BPD. Methods This double-blind randomized controlled trial (RCT) will assess the efficacy of home-based tDCS in reducing depressive symptoms in BPD patients who are experiencing moderate to severe depressive episodes. A total of 60 participants will be randomized, following a two-week online psychoeducation, to receive either active or sham tDCS in 14 sessions over one week. The primary outcome is the feasibility of home-based tDCS in remote and urban areas. The secondary aim is to obtain a preliminary assessment of the efficacy of 14 home-based tDCS sessions in reducing depressive symptoms in BPD patients with moderate to severe depressive episodes and BPD symptoms. Exploratory analyses will evaluate the impact of tDCS on neuropsychological functioning, physical activity, and substance use. Sociodemographic variables will be considered in predicting treatment response. All assessments will be conducted at baseline, post-treatment, and during follow-ups up to three months after treatment ends. Discussion The findings will address the feasibility of tDCS in real-world settings, contributing to the development of scalable neuromodulation strategies for individuals with BPD and comorbid depression.