Transcranial Direct Current Stimulation as an Adjuvant Therapy for Major Depressive Disorder

Objective: Major depressive disorder (MDD) is a prevalent and debilitating mental health condition, often
accompanied by medical and psychiatric comorbidities. Effective treatment strategies are crucial to reducing symptoms and improving the quality of life for affected individuals. This study evaluates the effectiveness of transcranial direct current stimulation as an adjunctive treatment for MDD, analyzing its impact on
depressive symptom reduction, safety, tolerability, and effectiveness when combined with conventional
pharmacological treatments.

Methods: A historical cohort study was conducted with 60 participants diagnosed with MDD. The Hamilton
Depression Scale and 9-Item Patient Health Questionnaire were used to measure depressive symptom
severity. Pre- and post-treatment scores were analyzed using ANOVA, with significance set at P < .05. Effect
sizes were calculated to quantify the magnitude of treatment effects. Demographic data, comorbidities,
and concurrent pharmacological treatments were also recorded.

Results: The cohort had an average age of 44.22 ± 19.8 years, with 43 (71.7%) women and 17 (28.3%) men.
Anxiety and insomnia were common, reported by 73.3% and 81.7% of participants, respectively, with 65%
experiencing both. Medical comorbidities were present in 56.7% of participants. Antidepressant use was
noted in 43.3%, with sertraline and escitalopram being the most frequently prescribed. Post-treatment
Hamilton Depression Rating Scale scores decreased from 24.23 to 6.78 (P < .01), reflecting a 72.02% reduction. 9-Item Patient Health Questionnaire scores dropped from 17.83 to 4.67 (P < .01), a 73.81% reduction.
No adverse effects were observed, supporting the intervention’s tolerability.

Conclusion: Transcranial direct current stimulation, as an adjunct to pharmacological therapy, significantly
reduces depressive symptoms in individuals with MDD. These findings support its use as an effective and
tolerable treatment option, especially for patients with comorbid medical and psychiatric conditions.

Cite this article as: Moya-Sánchez DN, Ochoa-Madrigal MG, Meneses-Luna Ó, et al. Transcranial direct current stimulation
as an adjuvant therapy for major depressive disorder. Neuropsychiatr Invest. 2025, 63, 0020, doi:10.5152/NeuropsychiatricInvest.2025.25020.