A new study finds that brain stimulation using electrical currents can help reduce depression symptoms. But not all methods work the same way, and the results depend on the type of depression and other health conditions a person may have.
Researchers from the Mayo Clinic analyzed data from 88 clinical trials with over 5,500 participants. Their goal was to evaluate how different types of transcranial electrical stimulation (tES) affect depression. The study was published online on June 18 in JAMA Network Open.
Key Findings: Different Methods, Different Benefits
The study looked at three main types of brain stimulation:
- Transcranial direct current stimulation (tDCS)
- Transcranial alternating current stimulation (tACS)
- Transcranial random noise stimulation (tRNS)
Overall, tES was linked to a meaningful drop in depression symptoms when compared to no treatment or fake (sham) stimulation. People with depression and other physical or mental health conditions appeared to benefit the most.
tDCS Helps More With Comorbid Conditions
tDCS, the most studied method, was especially helpful for people who had depression along with other health issues, like chronic illness or another mental health condition. These patients showed greater improvements than those with depression alone.
When tDCS was combined with antidepressant medication, results improved further. The combination led to greater symptom relief and higher response rates compared to fake stimulation with medication.
tACS Shows Promise for Major Depression
tACS also showed strong benefits for people with major depressive disorder (MDD). Participants receiving this treatment had lower depression scores and better response rates than those given sham treatment.
tRNS Didn’t Show Clear Benefits
Unlike tDCS and tACS, the third method—tRNS—did not produce significant improvements in symptoms or response rates in any depression group.
Safety and Tolerability
Most side effects linked to tES were mild or moderate, such as tingling or itching on the scalp. Serious side effects were rare, and the researchers concluded that tES is generally safe and well-tolerated.
Stimulation targeting the left dorsolateral prefrontal cortex (a brain area involved in mood regulation) appeared to improve outcomes across several methods.
Expert Insight and Recommendations
“These findings suggest that tES is safe, with only minor side effects, and may offer real benefits for people with depression—especially those with other health issues,” the authors wrote. However, they caution that more research is needed to determine the best way to use these therapies for individual patients.
The researchers recommend further studies to refine treatment settings and develop personalized tES protocols based on patient characteristics.
Study Details and Limitations
This large meta-analysis was led by Dr. Caili Ren of the Mayo Clinic in Rochester, Minnesota. It included mostly adults (average age 43) and 60% of participants were women. Funding came from the Mayo Clinic and the National Center for Advancing Translational Sciences.
However, the authors acknowledged several limitations:
- Most data came from tDCS studies, limiting deeper analysis of tACS and tRNS.
- Some studies didn’t clearly separate tDCS used alone from when it was used with medication.
- Nearly half the studies didn’t report safety data, making it hard to assess risks fully.
The severity of participants’ depression was not always recorded, and publication bias may have affected the results, especially for tDCS in patients with other medical conditions.
Funding and Disclosures
The study received financial support from public institutions. However, one of the authors disclosed multiple connections to industry, including advisory roles, company leadership positions, and patents related to brain stimulation technologies. Full disclosure details are available in the original journal article.
Conclusion
This new research highlights the potential of noninvasive brain stimulation to relieve depression, especially for people with other health issues. While tDCS and tACS appear effective, more studies are needed to explore the full potential of these treatments and tailor them to individual needs.
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