Neurocognitive effects of transcranial direct current stimulation in obsessive-compulsive disorder: a systematic review

Abstract

Transcranial direct current stimulation (tDCS) has been used with increasing frequency as a therapeutic tool to alleviate clinical symptoms of obsessive compulsive-disorder (OCD). However, little is known about the effects of tDCS on neurocognitive functioning among OCD patients. The aim of this review was to provide a comprehensive overview of the literature examining the effects of tDCS on specific neurocognitive functions in OCD. A literature search following PRISMA guidelines was conducted on the following databases: PubMed, PsycINFO, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science. The search yielded 4 results: one randomized, sham-controlled study (20 patients), one randomized, controlled, partial crossover trial (12 patients), one open-label study (5 patients), and one randomized, double-blind, sham-controlled, parallel-group trial (37 patients). A total of 51 patients received active tDCS with some diversity in electrode montages targeting the dorsolateral prefrontal cortex, the pre-supplementary motor area, or the orbitofrontal cortex. tDCS was associated with improved decision-making in study 1, enhanced attentional monitoring and response inhibition in study 2, improved executive and inhibitory control in study 3, and reduced attentional bias and improved response inhibition and working memory in study 4. Limitations of this review include its small sample, the absence of a sham group in half of the studies, and the heterogeneity in tDCS parameters. These preliminary results highlight the need for future testing in randomized, sham-controlled trials to examine whether and how tDCS induces relevant cognitive benefits in OCD.

Keywords:

• Transcranial direct current stimulation
• obsessive-compulsive disorder (OCD)
• cognition
• inhibition
• decision-making

Ethics approval

This is a systematic review. The McMaster Research Ethics Board (MREB) has confirmed that no ethical approval is required.

Consent form

This is a systematic review. The authors used publicly accessible documents in the composition of this manuscript and, as such, informed consent was not a requirement.

Disclosure statement

The authors have no relevant financial or non-financial interests to disclose. The authors have no competing interests to declare that are relevant to the content of this article. All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.

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Funding

The author(s) reported there is no funding associated with the work featured in this article.