Brain 'Pacemaker' May Cure Depression

Deep brain stimulation, already approved to treat neurological conditions like Parkinson's disease, may be helpful for people with treatment-resistant depression.

Although most people with clinical depression find relief from their symptoms with psychotherapy, antidepressants, or a combination of the two, statistics suggest that about 30% experience treatment-resistant depression (TRD).

While treatment options are limited for people with TRD, reports suggest that ketamine, a schedule III controlled drug used as an anesthetic, may improve TRD symptoms. However, some research found that the drug performed the same as a placebo and did not provide symptom relief.

Electroconvulsive therapy (ECT), which involves delivering a low-impulse shock to the brain, is another treatment option for TRD. Although considered safe, ECT may be ineffective at treating severe, ongoing depressive symptoms in some individuals.

However, a new therapy for people enduring severe and difficult-to-treat depression is on the horizon. The treatment, called deep brain stimulation, is already used to treat certain neurological conditions.

Deep brain stimulation and depression

Deep brain stimulation (DBS) is an experimental treatment that involves a surgical procedure where doctors implant electrodes into specific areas in the brain. The electrodes are connected to a neurostimulator that sends impulses to brain areas associated with depression. The concept is similar to cardiac pacemakers that send electronic impulses to the heart.

Currently, the treatment is FDA-approved for treating specific neurological conditions, such as Parkinson's disease, obsessive-compulsive disorder (OCD), and dystonia.

Even though DBS treatment requires surgery and is a more invasive option, several studies investigating its impact on people with TRD have produced encouraging results.

For example, a study published in 2020 revealed that DBS continued to be effective in treating TRD 2 years after surgery. The study's authors note the findings support DBS as a viable option for people with treatment-resistant depression.

Moreover, a 2021 systematic review and meta-analysis of 17 studies found that, on average, 56% of people with TRD responded to treatment with DBS, and 35% experienced remission. TRD symptoms reoccurred in about 14% of participants.

Research published in 2023 found that at the end of a 24-week trial, 90% of participants with TRD undergoing DBS showed a robust clinical response to treatment, and 70% experienced remission.

Although the FDA has not approved DBS to treat depression, an Associated Press report indicates the agency is fast-tracking its review of a DBS device for TRD developed by Abbott Laboratories.

How does deep brain stimulation work for depression?

DBS works by stimulating brain circuitry associated with depression. To begin treatment with DBS, surgeons use brain images to determine where to implant the electrodes and create small holes in the skull to allow for placement.

Then, surgeons attach thin wires to the electrodes and hide the wires under the skin of the head, neck, and shoulders.

The procedure requires general anesthesia and takes about 4 hours to complete. One day later, the surgeons implant a small battery pack near the patient's collarbone and attach the wires leading to the electrodes. Then, a neurologist programs the device and works with the patient to find the settings that work best for symptom relief.

According to the American Association of Neurological Surgeons (AANS), risks associated with DBS include:

• A slight chance of brain hemorrhage, including stroke
• Infection
• Device malfunction
• Headache
• Worsening emotional symptoms
• A lack of response to treatment

Moreover, people with a DBS device may experience tingling in the face or limbs, loss of balance, or speech and vision issues during stimulation. The AANS says these potential risks and side effects are generally mild and reversible.

In general, people who might benefit from DBS are those who cannot tolerate medications or are experiencing a significantly reduced quality of life because of treatment failure.

Despite the promising outlook for deep brain stimulation as a potential treatment option for TRD, more research is needed. Specifically, scientists want to learn more about how to track a patient's progress after surgery to establish the effectiveness of this experimental treatment.