It’s estimated that around 30 percent of people with depression don’t respond to typical antidepressants. This is known as treatment-resistant depression, and brain stimulation therapies can be life-changing for people who experience it.
“Brain stimulation therapies involve the application of [electric] energy over specific brain regions to modulate the function of neural circuits,” Joshua Berman, M.D., Ph.D., assistant professor of psychiatry at Columbia University Irving Medical Center, tells SELF. This can help alleviate symptoms of depression or other mental illnesses that aren’t responding to typical treatments, such as bipolar disorder.
The five main types of brain stimulation therapies used to treat mental illness are electroconvulsive therapy, vagus nerve stimulation, deep brain stimulation, repetitive transcranial magnetic stimulation, and magnetic seizure therapy. Let’s explore what they are, how they work, and their potential risks.
Electroconvulsive therapy (ECT)
In addition to severe or treatment-resistant depression, ECT may be used to treat conditions like schizophrenia and bipolar disorder if you’re not responding to treatment or if you need extremely prompt treatment due to suicidal ideation, according to the Mayo Clinic. While many insurers currently cover ECT to treat certain conditions, the FDA proposed changing the classification of ECT devices back in 2015 from class III medical devices to class II medical devices, while also putting certain restrictions on who should use the therapy (due to potential risks, which we’ll discuss in a bit). That proposed reclassification is still ongoing.
So, let’s say your medical care team has decided you’re a good candidate for ECT. In each session, you’ll be anesthetized to prevent pain and given a muscle relaxant, the National Institute of Mental Health (NIMH) explains. Then, doctors will expose you to a direct electrical current via electrodes on your scalp. The current triggers a short seizure, usually under a minute long. Again, you shouldn’t feel any discomfort, which might be hard to believe. But that’s the beauty of anesthesia.
Five to 10 minutes later, you’ll wake up and should be able to get back to your usual activities within an hour, according to the NIMH. Although it obviously depends on what your doctor thinks is best, a person receiving ECT will typically get a few treatments a week and may experience less severe depression (or other mental health symptoms) within six to 12 treatments.
“We don’t know the exact mechanisms by which ECT works,” Dr. Berman says. One theory holds that the seizures change blood flow in various parts of the brain such as the amygdala, which is linked with your emotions. There’s also evidence that ECT affects neurotransmitters that impact your mood, like serotonin and dopamine, which some antidepressants also target. The difference is that ECT seems to engage the same brain systems as conventional antidepressants more powerfully and possibly more quickly as well, Dr. Berman explains.
The most common side effects someone might experience after ECT are headaches, an upset stomach, muscle aches, and memory loss, the NIMH says. The memory loss might sound alarming, but it’s usually temporary, and it seems to be less severe if the ECT electrodes are on just one side of the head instead of both. This is known as unilateral ECT, and it’s the more modern take on bilateral ECT, the older form of the treatment that is linked with more intense memory issues, the NIMH says.
Vagus nerve stimulation (VNS)
Vagus nerve stimulation was initially developed as a treatment for the seizure disorder epilepsy, and in a happy accident, scientists discovered that it could help with depression as well, the NIMH explains. So, the FDA approved VNS for treatment-resistant depression in 2005.
Although VNS is a brain stimulation treatment, it actually starts outside your head. If you’re getting this kind of therapy, doctors will surgically implant a tool called a pulse generator into the upper left portion of your chest, the NIMH explains. An electrical wire connects the pulse generator to your vagus nerve, which runs from your brain through your neck and into your chest and abdomen. From its command center in your chest, the pulse generator will send bursts of electric currents to your brain every couple of minutes. Pulse generators typically work for around 10 years before they need to be replaced, the NIMH says.