Brain Stimulation Improves Depression, Finds New Study

The novel method, called transcranial alternating current stimulation, proved successful in 70 percent of the study's participants.
Loukia Papadopoulos

New research is revealing that brain simulation conducted with a weak alternating electrical current can reduce depression symptoms. The novel method, called transcranial alternating current stimulation (tACS), proved successful in 70 percent of the study's participants. 


"We conducted a small study of 32 people because this sort of approach had never been done before," said senior author Flavio Frohlich, Ph.D., associate professor of psychiatry and director of the Carolina Center for Neurostimulation. 

"Now that we've documented how this kind of tACS can reduce depression symptoms, we can fine tune our approach to help many people in a relatively inexpensive, noninvasive way."

Alpha oscillations at play

tACS is based on previous research that found that people with depression featured imbalanced alpha oscillations. The waves were overactive in the left frontal cortex.

As such, Frohlich and his team stipulated that they could alleviate depression symptoms by bringing the alpha oscillations on the left side back in synch with the alpha oscillations in the right.

To test their theory, they recruited 32 participants diagnosed with depression. Prior to beginning the study, they evaluated them using the Montgomery-Åsberg Depression Rating Scale (MADRS).

They then separated them into three groups. One group received a sham placebo stimulation, another a 40-Hertz tACS intervention, and the third a 10-Hertz tACS electrical current.

A successful trial

Each participant took the MADRS test throughout the trial period. After two weeks of the treatment, Frohlich and his team found that 70 percent of people in the treatment group had at least a 50 percent reduction of depression symptoms.

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In addition, some of the participants had such significant decreases that Frohlich's team is currently writing case-studies on them. Participants in the other groups showed no such signs of improvement.

"It's important to note that this is a first-of-its-kind study," Frohlich said.

"When we started this research with computer simulations and preclinical studies, it was unclear if we would see an effect in people days after tACS treatment - let alone if tACS could become a treatment for psychiatric illnesses. It was unclear what would happen if we treated people several days in a row or what effect we might see weeks later. So, the fact that we've seen such positive results from this study gives me confidence our approach could help many people with depression."

The study is published in Translational Psychiatry.

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