Authors' objectives: The objective of this technology review was to assess the effectiveness, safety, and cost-effectiveness of transcranial direct current stimulation (tDCS) for depression and schizophrenia

Authors' results and conclusions: A total of 410 records were identified through the Ovid interface, Pubmed and other sources. After screening, 46 articles were assessed for eligibility and 344 records were excluded. After reading, appraising, and applying the inclusion and exclusion criteria to the full-text articles, 20 were included while the other 26 were excluded since the studies had irrelevant populations and few were narrative reviews. Twenty fulltext articles finally selected for this review were one umbrella review, 12 systematic reviews and meta-analyses, five randomised controlled trials, one cross-sectional study, and one cost analysis. Efficacy/ effectiveness Transcranial direct current stimulation (TDCS) for depression Multiple meta-analyses and systematic reviews demonstrated that transcranial direct current stimulation (tDCS) appeared as an effective treatment for major depressive disorder (MDD), showing significant improvements in depressive symptoms, with moderate evidence for improved response rates and, to a lesser extent, remission rates when compared to sham treatments. The effectiveness of tDCS appears to be enhanced when combined with medication, while evidence of its standalone efficacy remains limited. However, the quality of evidence is mixed, and the long-term effectiveness of tDCS is still uncertain. Transcranial direct current stimulation (TDCS) for schizophrenia Limited retrievable evidence suggests that tDCS has shown limited ability to reduce positive symptoms, improve executive function, working memory, attention, and auditory hallucinations. Some studies reported significant improvements in negative symptoms particularly with higher frequency stimulation, improvement in self-awareness, and psychological domain of life quality, however, the effects were shortterm. The overall effectiveness of tDCS in treating schizophrenia appears inconsistent with mixed results across different studies. Safety Evidence consistently shows that transcranial direct current stimulation (tDCS) appears safe and well-tolerated intervention for both depression and schizophrenia. Multiple systematic reviews, metaanalyses, and randomized controlled trials report no significant differences in dropout rates or adverse events between active tDCS and sham groups. Common mild side effects include itching, tingling, and local discomfort, with no serious or irreversible adverse effects documented across numerous studies. Organisational Issues Training Training for tDCS focuses on proper device use and safety. Researchers and technicians must learn equipment setup, correct electrode placement, and dosage accuracy. Physicians should oversee higher-risk procedures, but no specific professional qualifications are required for operators. Training includes managing adverse effects like skin burns and cognitive changes, with competency assessments after instruction. Future certification for trainers may be required. Guidelines Clinical practice guidelines on transcranial direct current stimulation (tDCS) for depression and schizophrenia generally acknowledge its potential but fall short of making specific recommendations. For depression, some guidelines note the efficacy of tDCS, especially in non-drug-resistant cases, but no formal recommendation is provided. In schizophrenia, the evidence is mixed, with meta-analyses showing limited or no significant effects on symptoms, leading to a lack of endorsement for its use. Overall, while tDCS is recognized as a promising treatment, particularly for depression, more research is needed to support its broader clinical application, and its use should be carefully supervised by trained psychiatrists. Ethical Issues Ethical concerns in transcranial stimulation research focus on informed consent, risk-benefit analysis, and the fair distribution of outcomes. Using tDCS for neuroenhancement raises ethical issues, such as widening social inequalities and risks related to unknown long-term behavioral effects. An international survey among tDCS researchers found tDCS to be seen as partly effective in research and clinical contexts, but with greater ethical concerns for enhancement use. Most researchers opposed public availability due to safety risks, emphasizing the need for stricter regulations and more clinical trials. Woodham et al. (2021) also stressed the importance of regulation, particularly with the rise of DIY use, and highlighted concerns over maladaptive long-term neuroplastic changes, calling for professional oversight to ensure safety. CONCLUSION In conclusion, transcranial direct current stimulation (tDCS) shows potential as a treatment for depression, particularly in reducing depressive symptoms and improving response rates compared to sham treatments. While tDCS appears effective, its benefits may not surpass those of traditional antidepressants, and its effectiveness as a standalone treatment remains limited. The combination of tDCS with medication shows more significant improvements, suggesting that tDCS might be best used as an adjunctive therapy. However, its effectiveness for schizophrenia is less clear, with limited and inconclusive evidence regarding its impact on negative and cognitive symptoms. In terms of safety, tDCS is generally well-tolerated, with a relatively low incidence of adverse effects. The use of tDCS for MDD is acknowledged though it is not specifically recommended in many guideline

Authors' methods: A systematic search was conducted on the following databases without any restriction on publication language and publication status. The Ovid interface: Ovid MEDLINE(R) and Epub Ahead of Print, InProcess, In-Data-Review & Other Non-Indexed Citations and Daily 1946 to Dec 1st, 2023. Searches were also run in Cochrane Embase, PubMed, and INAHTA databases. Google was used to search for additional web-based materials and information. Additional articles were identified by reviewing the references of retrieved articles. The last search was conducted on 17th July 2024.

Project Status: Completed

URL for project: https://www.moh.gov.my/index.php/database_stores/store_view_page/30/418

Year Published: 2024

URL for published report: https://www.moh.gov.my/index.php/database_stores/store_view_page/30/418

English language abstract: An English language summary is available

Publication Type: Mini HTA

Country: Malaysia

Organisation Name: Malaysian Health Technology Assessment

Contact Address: Malaysian Health Technology Assessment Section, Ministry of Health Malaysia, Federal Government Administrative Centre, Level 4, Block E1, Parcel E, 62590 Putrajaya Malaysia Tel: +603 8883 1229

Contact Name: htamalaysia@moh.gov.my

Contact Email: htamalaysia@moh.gov.my

Copyright: Malaysian Health Technology Assessment Section (MaHTAS)