Effects of Transcranial Direct Current Stimulation on Cognitive Deficits in Depression: A Systematic Review.

Area of Science:

• Neuroscience
• Psychiatry
• Clinical Psychology

Background:

• Major depressive disorder (MDD) is a leading global cause of mental health burden, with many patients not achieving remission.
• Transcranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation technique used for MDD and bipolar disorder.
• Recent research has significantly increased the publication of studies on tDCS for cognitive symptoms in MDD.

Approach:

• A systematic review was conducted using 5 electronic databases up to March 21, 2022.
• Included randomized controlled trials (RCTs) evaluating tDCS in adults (≥18 years) diagnosed with MDD or bipolar disorder.
• Adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines ensured methodological rigor.

Key Points:

• The review included 14 studies with 972 participants (60.5% female, mean age 47.0 years).
• Seven of the 14 studies reported significant cognitive improvements with active tDCS compared to sham treatment.
• Most studies reported mild-to-moderate side effects, and all used DSM criteria for diagnosis.

Conclusions:

• Current evidence suggests limited efficacy of tDCS for cognitive impairments in MDD and bipolar disorder.
• Future research should explore machine learning to predict tDCS responders and non-responders.
• Personalized treatment approaches could enhance the clinical benefits of tDCS for mood disorders.