What is TMS?
TMS, otherwise known as Transcranial Magnetic Stimulation, is an FDA approved, localized, non-invansive treatment option for major depression. It involves using short pulses of magnetic energy to alter the activity of nerve cells in the brain.
How does it work?
Magnetic pulses produced by the TMS system are directed to specific brain areas related to mood regulation. The magnetic field generated by TMS is the same type and strength generated by MRI machines (approximately 1.5 Tesla). TMS pulses stimulate electric currents in nearby brain tissue, which subsequently cause neurons to become more active.
The electromagnetic stimulation produced by TMS acts on hypoactive brain regions in the following ways:
- facilitates release of neurotransmitters, (serotonin, norepinephrine and dopamine)
- optimizes blood flow
- induces release of brain-derived neurotrophic growth factor (BDNF), an important chemical that influences connections between brain cells
TMS is considered an outpatient procedure and is performed in our offices. The treatment is administered daily over a course of 4-5 weeks. Each daily treatment lasts approximately 20 minutes.
Patients do not require anesthesia. They remain awake and can resume their normal daily activity immediately after treatment.
Tolerability and Side Effects
The safety and tolerance of TMS has been affirmed through several large, randomized control studies. It has been shown to be safe in >10,000 active treatments performed in clinical trials with less than 5% of patients discontinuing treatment due to side effects.
TMS is non-systemic, so it does not cause side effects such as weight gain, sexual dysfunction, nausea, dry mouth and/or sedation – all of which are associated with oral antidepressant treatment.
The most commonly reported side effect with TMS is scalp discomfort, which is apparent in the first week and generally subsides over the course of treatment.
Response Rates and Durability
Based on several randomized controlled clinical trials, two out of three patients experienced either a 50% reduction in depressive symptoms (as measured by validated depression rating scales) or complete remission.
The durability of TMS has been demonstrated in several studies. In a 1-year multisite observational study conducted in 120 patients who met criteria for response or remission following TMS course, approximately 60% continued to meet response criteria 12 months later.
Contraindications and Potential Risks
Because TMS involves the use of magnetic fields it should not be performed in patients who have conductive, ferromagnetic or other magnetic sensitive metals implanted in their head or are non- removable and are within 30 cm of the treatment coil. Examples include cochlear implants, implanted electrodes/stimulators, aneurysm clips or coils, stents and bulleted fragments.
There is a rare risk of inadvertent seizure with TMS. However the risk is small and estimated to be <0.003% with NeuroStar. This is less than the risk of seizure reported for certain antidepressant medications.
History of TMS and Society Endorsements
The technology of using magnetic fields to modulate brain activity has been around for many years. There have been >30 controlled clinical research trials studying TMS, including three large, multisite, randomized controlled trials. Two of these randomized controlled trials were industry-sponsored trials that led to the FDA clearance of NeuroStar TMS Therapy System in 2008. The third randomized controlled trial was conducted by the NIMH (National Institute of Mental Health), which provided industry independent evidence for TMS as a viable treatment option for depression.
In 2013, the FDA allowed for a second TMS system, Brainsway, to be marketed in the United States. Two additional devices were cleared in 2015, Magstim (UK) and Tonica. TMS is a recognized treatment for MDD in routine, clinical practice. It is endorsed by several specialty organizations, including but not limited to the American Psychiatric Association, the World Federation of Societies for Biological Psychiatry and the Canadian Network for Mood and Anxiety Disorder.
TMS vs. ECT
Contrary to popular belief, TMS is not the same as ECT (electroshock therapy). While ECT is an effective treatment for severe, intractable depression, it requires the use of anesthesia and relies on the intentional induction of seizures. ECT is also commonly associated with short-term confusion and/or memory loss. This is not the case with TMS treatment.