TMS: Success in Treating Resistant Depression

Transcranial magnetic stimulation (TMS) is a successful treatment for people suffering from depression when medications and psychotherapy have failed. TMS targets a specific area of the brain and delivers magnetic stimulation to help control impulses and emotions.

Key takeaways:
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    Clinical depression is the most commonly diagnosed mental health disorder in the US.
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    One out of three people treated for depression will be resistant to medication.
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    TMS is a non-invasive, effective treatment for people with resistant depression.
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    Magnetic pulses are directed to the brain’s prefrontal cortex, the area that controls mood, well-being, and feelings of pleasure.
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    TMS therapy requires a commitment to daily treatment for at least a month.

First discovered in 1985, TMS treats depression as well as other mental health disorders. In 2007, the FDA approved treatment for major depressive disorder (MDD), also called clinical depression, which is the most commonly diagnosed psychiatric disorder in the United States.

Every year 10%-15% of the population is diagnosed with major depression, and of those treated, 30% will be resistant to conventional therapy. One out of three people using antidepressants to treat their depression symptoms experiences treatment-resistant depression (TRD). Doctors diagnose TRD when at least two different kinds of antidepressant medications have been tried and failed. If, after taking therapeutic levels of antidepressants for a specific amount of time, the person still has depression symptoms, the patient is considered treatment resistant.

What is transcranial magnetic stimulation?

No analgesia or sedation is used during the non-invasive TMS therapy. There are no injections and no IVs, and the patient remains awake for the whole procedure.

Transcranial magnetic stimulation is a form of brain stimulation that uses an insulated coil to create a magnetic field when it reacts with the energy produced by the brain. When brain cells and nerves (neurons) send and receive information, energy is created. This energy is magnified by the magnetic coil, which delivers rapid energy bursts to the area of the brain that controls internal decision-making, mood, sense of well-being, and feelings of pleasure. This area of the brain is called the “dorsolateral prefrontal cortex”, or DLPFC. Researchers believe that the DLPFC is under-stimulated with inadequate neuron activity in a depressed person. Transcranial magnetic stimulation directs pulses to this area, exciting the neural pathways and interrupting depression.

What happens to the patient when receiving TMS?

The first TMS appointment is for taking measurements and setting up the device for therapy. Every patient is unique, so magnetic coil placement and stimulation levels for effective treatment vary.

The patient reclines in a comfortable chair throughout the treatment. The medical professional first take head measurements to determine proper magnetic coil placement and locates the area of the brain called the “motor cortex”. The coil is placed on the left side of the head, over the motor cortex, and the physician gives a few brief magnetic pulses to elicit a small finger movement. This is known as the “motor threshold” and determines the correct dosage for the treatment. Just in front of the motor cortex is the DLPFC — the area involved in treating depression. Magnetic stimulation will not affect the entire areas of the brain, the magnetic impulses only reach a few centimeters under the coil.

The treatments take approximately 30-40 minutes, and the magnetic stimulation causes a tapping feeling on the head with a clicking sound that is similar to an MRI scan. Earplugs are worn to protect the ears from noise because the location of the coil is near the ear. Some patients, however, relax enough to sleep through their treatments.

The magnetic waves repetitively stimulate the brain — on for four seconds, off for 26 seconds. This repetitive cycle is the best treatment cycle for depression and is known as “rTMS”, or repetitive TMS. There are other treatments, such as deep transcranial magnetic stimulation (dTMS), which is deeper penetrating brain stimulation used for depression along with anxiety symptoms.

Common side effects

  • Tinnitus (ringing in the ears)
  • Lightheadedness
  • Dizziness during and soon after treatment
  • Scalp discomfort
  • Facial tingling
  • Headache

Common side effects are usually mild and short-lived. They may occur during or shortly after treatment and often resolve within the first few treatments. Tylenol, aspirin, or ibuprofen is taken as pretreatment and usually eliminate headaches or scalp pain. Commonly, these symptoms lessen or go away with successive treatments.

Uncommon side effects

  • Seizures
  • Hearing loss
  • Mania

These uncommon side effects are rare. However, patients with bipolar disorder stand a higher chance of a manic episode after treatment, and anyone with a history of epilepsy is contraindicated from receiving TMS treatment.

Treatment protocol

Transcranial magnetic stimulation treatment requires a series of sessions. Typically, the patient goes five times a week for 4-6 weeks. Patients can usually drive themselves to and from their appointment and maintain their regular activities throughout treatment. Most patients also take antidepressant medication along with TMS treatment. People with non-removable metal in their heads are unable to receive treatment, and others must fill out a pre-therapy form detailing any history of metal implanted in the body. Braces and dental fillings are fine, but aneurysm clips, head or neck stents, metallic tattoos, or shrapnel are contraindicated due to the magnetic aspect of treatment.

Studies show that 60% of patients receiving TMS treatment for depression experienced 50% fewer symptoms. Furthermore, about 30% of patients had no depression symptoms after treatment and no longer met the criteria for their diagnosis.

The use of TMS is being researched, and positive results have been seen with many other illnesses and chronic diseases. Trials are underway evaluating the effectiveness and developing treatment protocols for the following disorders:

  • Chronic pain
  • Obsessive-compulsive disorder (OCD)
  • Anxiety disorder
  • Drug addiction
  • Alcoholism
  • Post-traumatic stress disorder (PTSD)
  • Schizophrenia
  • Alzheimer’s disease
  • Parkinson’s disease
  • Stroke recovery
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