Transcranial magnetic stimulation (TMS) is a noninvasive, device delivering pulsed, magnetic fields to induce an electric current in the cerebral cortex. When used as an antidepressant, TMS produces clinical benefit without the systemic adverse effects associated with medications, and has no adverse cognitive effects.

What is Depression?

Major Depressive Disorder (MDD) is a mental disorder characterized by episodes of all-encompassing low mood accompanied by low self-esteem and loss of interest or pleasure in normally enjoyable activities. This cluster of symptoms was named, described and classified as one of the mood disorders in the 1980 edition of the American Psychiatric Association's diagnostic manual. Major Depressive Disorder is a disabling condition that adversely affects a person's family, work or school life, sleeping and eating habits, and general health.

A person having a major depressive episode usually exhibits a very low mood, which pervades all aspects of life, and an inability to experience pleasure in activities that were formerly enjoyed. Depressed people may be preoccupied with, or ruminate over, thoughts and feelings of worthlessness, inappropriate guilt or regret, helplessness, hopelessness, and self-hatred.

Traditionally Major Depressive Disorder has been treated using psychotherapy, antidepressant medication and Electroconvulsive Therapy (ECT). However, from the middle of the 1990es repetitive Transcranial Magnetic Stimulation (rTMS) has been used for treatment of major depressive disorder.

The evidence for the clinical efficacy of TMS in treating major depression spans more than 30 randomized, controlled trials involving more than 2,000 patients.

Overall, these reports represent a comprehensive and consistent literature in which conclusions support the specific use of high-frequency TMS to the left dorsolateral prefrontal cortex in patients who have not benefited from antidepressant medication.

How it works

During a TMS session, an electromagnetic coil is placed against your scalp near your forehead. The electromagnet painlessly delivers a magnetic pulse that stimulates nerve cells in the region of your brain involved in mood control and depression. And it may activate regions of the brain that have decreased activity in people with depression.

Though the biology of why rTMS works isn't completely understood, the stimulation appears to affect how this part of the brain is working, which in turn seems to ease depression symptoms and improve mood.

Treatment for depression involves delivering repetitive magnetic pulses, so it's called repetitive TMS or rTMS.

Your first treatment

Before treatment begins, your doctor will need to identify the best place to put the magnets on your head and the best dose of magnetic energy for you. Your first appointment typically lasts about 60 minutes.

Most likely, during your first appointment:

 You'll be taken to a treatment room, asked to sit in a reclining chair and given earplugs to wear during the procedure.

 An electromagnetic coil will be placed against your head and switched off and on repeatedly to produce stimulating pulses. This results in a tapping or clicking sound that usually lasts for a few seconds, followed by a pause. You'll also feel a tapping sensation on your forehead. This part of the process is called mapping.

 Your doctor will determine the amount of magnetic energy needed by increasing the magnetic dose until your fingers or hands twitch. Known as your motor threshold, this is used as a reference point in determining the right dose for you. During the course of treatment, the amount of stimulation can be changed, depending on your symptoms and side effects.

During each treatment

Once the coil placement and dose are identified, you're ready to begin. Here's what to expect during each treatment:

 You'll sit in a comfortable chair, wearing ear plugs, with the magnetic coil placed against your head.

 When the machine is turned on, you'll hear clicking sounds and feel tapping on your forehead.

 The procedure will last about 40 minutes, and you'll remain awake and alert. You may feel some scalp discomfort during the treatment and for a short time afterward.

After each treatment

You can return to your normal daily activities after your treatment. Typically, between treatments, you can expect to work and drive. There are different ways to perform the procedure. Techniques may change as experts learn more about the most effective ways to perform treatments.