Delayed tDCS Effects in Treatment-Resistant Depression: A Pilot Study

Author Names

Min-Shan Li, Xiang-Dong Du, Hsiao-Chi Chu, Yen-Ying Liao, Wen Pan, Zhe Li, Galen Chin-Lun Hung

Published Date: April 2019

Journal Name: BMC Psychiatry

Abstract

This pilot study investigates the delayed effects of bifrontal transcranial direct current stimulation (tDCS) in patients with treatment-resistant depression (TRD). The study enrolled 18 patients diagnosed with either unipolar or bipolar depression, who had failed to respond to at least two adequate trials of pharmacotherapy. Over 12 tDCS sessions, significant improvements in depression scores were observed, particularly in the 6th and 8th weeks. Cognitive performance also showed improvements in specific areas, such as paired association and social cognition. The study suggests that tDCS can be a viable option for TRD, but its effects may take time to manifest fully.

Key Concepts

• Transcranial Direct Current Stimulation (tDCS): A non-invasive brain stimulation technique that uses low-intensity electrical currents to modulate neuronal activity, potentially improving symptoms of depression.

• Treatment-Resistant Depression (TRD): A form of depression that does not respond to traditional treatment methods, such as medication and psychotherapy, necessitating alternative approaches.

• Cognitive Performance: The mental processes of perception, memory, judgment, and reasoning, assessed in this study to evaluate the effects of tDCS.

• Literature Review: Prior studies have shown mixed results for tDCS in treating TRD. This study contributes to the ongoing research by examining delayed effects and cognitive outcomes.

Procedure Highlights - Research Methodology

1. Study Design: A pilot study with a pretest-posttest design, involving 18 patients diagnosed with TRD.

2. Participants: 18 patients with unipolar (n=13) or bipolar (n=5) depression who did not respond to at least two adequate trials of antidepressants.

3. tDCS Intervention: 12 sessions of tDCS were administered over the left dorsolateral prefrontal cortex (DLPFC), with anode placement at F3 and cathode at F4, delivering 2 mA current for 30 minutes per session over ten working days, with additional sessions at the 4th and 6th weeks.

4. Outcome Measures: Depression severity was measured using the Montgomery–Åsberg Depression Rating Scale (MADRS) at baseline, 2nd, 4th, 6th, and 8th weeks. Cognitive performance was assessed using a computerized battery evaluating various cognitive domains.

Results - Findings of the Research

• Depression Improvement: The study found significant reductions in MADRS scores from baseline (mean=29.6, SD=9.7) to the 6th week (mean=22.9, SD=11.7, p=0.03) and the 8th week (mean=21.5, SD=10.3, p=0.01). Six participants (33.3%) were identified as responders, showing a more pronounced decrease in MADRS scores.

• Cognitive Performance: Significant improvements were observed in the accuracy of paired association tasks (p=0.017) and social cognition (p=0.047) in the 8th week, indicating potential cognitive benefits of tDCS.

• Adverse Effects: The tDCS was generally well-tolerated, with some patients reporting mild side effects such as headache and scalp discomfort.

Discussion and Conclusion of the Research

The findings suggest that tDCS can be an effective treatment option for patients with treatment-resistant depression, especially when considering its delayed effects. The study highlights the importance of identifying predictors of therapeutic response to tailor tDCS treatment more effectively. The results also underscore the need for larger controlled studies with optimized treatment protocols and longer observation periods to validate these preliminary findings.

Link to the Original Paper

Delayed effect of bifrontal transcranial direct current stimulation in patients with treatment-resistant depression: a pilot study

Author Information

• Min-Shan Li: Blossom Clinic of Psychosomatic Medicine, Taipei, Taiwan.

• Xiang-Dong Du: Suzhou Guangji Hospital, Suzhou, China.

• Hsiao-Chi Chu: Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan.

• Yen-Ying Liao: Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan.

• Wen Pan: Affiliated Guangji Hospital of Soochow University, Suzhou, China.

• Zhe Li: Suzhou Guangji Hospital, Suzhou, China.

• Galen Chin-Lun Hung: Department of Public Health, School of Medicine, National Yang-Ming University, Taipei, Taiwan.

Mave Health Disclaimer

The content provided here is an interpretation of a research paper for educational purposes. It is simplified to make the findings accessible to a general audience. For detailed information, please refer to the original research paper.