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Transcranial Magnetic Stimulation (TMS) therapy has become more popular recently as an alternative treatment to common psychic disorders like depression and anxiety, when other methods like antidepressant medication or psychotherapy fail to give a side-effect-free rapid response. The main idea of TMS is to activate the brain directly, by inducing local electric current flow following the application of a short magnetic field over the head. Even though the absence of drugs side effects and quick results appear to be appealing, there are also some drawbacks to be carefully considered, strictly with medical consultation.
TMS is administered by placing an electromagnetic coil over left prefrontal cortex (an area that often shows abnormal electrical activity in depression patients) , which generates a short magnetic field that passes through the scalp to induce neuronal electric currents. The neurotransmitter imbalance which is believed to be the cause of depression is rectified by this induced modulation. Even though it is not entirely clear how TMS is acting on the brain, it is well known that neurons are more receptive to treatments when they’re actively engaged in some tasks. In this direction, TMS combined with a cognitive-behavioral therapy is a promising method for overcoming depressive symptoms.
The main advantage is that it is applied when patients are awake and alert, thus instantaneous feedback about the level of discomfort can be easily obtained. TMS therapy can be safe when used both with and without antidepressant medications. Typically, results are achieved within one or two weeks from the start of the treatment. Compared to other non-invasive brain stimulation techniques, like electro and magneto convulsive therapies, TMS is more focal, has fewer side effects and is usually better tolerated. Also, TMS is free from the risks related to implant surgery and from the movement disorders that may be associated with invasive brain stimulation techniques like vagus nerve stimulation. But TMS can cause mild headaches, dizziness and slight discomfort depending on the scalp location and sometimes twitch in jaw or face muscles.
TMS has been approved for treating antidepressant-treatment-resistant depression in USA (since 2008), Canada (2002), Australia (2003), Europe (2010) and Israel . TMS is successfully applied in treating vascular depression following stroke and schizophrenia. It has been CE approved in Europe for the treatment of bipolar disorder, PTSD, chronic pain, OCD, and adult AD/HD . In a study of 301 participants who had antidepressant-treatment-resistant depression, nearly half of them showed complete or partial improvement in symptoms . Clinical studies in four US university hospitals showed that daily left prefrontal TMS as monotherapy produced statistically significant and clinically meaningful antidepressant therapeutic effects greater than TMS inactive treatment . 75% of the people who have TMS treatment combined with cognitive behavioral therapy experience a significant reduction of depression symptoms .
A typical course of TMS therapy for depression involves 20 to 30 sessions; each session lasts 30 to 60 minutes, given in 3 to 5 times per week . The full course of therapy can cost $6,000 to $12,000 in US and €2500 to €4000 in Europe . Even though the treatment is a bit expensive, the number of healthcare insurance companies that cover TMS therapy has been on the rise.
TMS should be administrated with strict medical consultation as it is not appealing for patients with history of seizure, metallic implants or other neurological disorders. Follow-up courses and consultations are necessary to monitor any long lasting side effects or improvements in depression symptoms. More research is needed to reveal gaps of knowledge in this technique.
References: George MS, Lisanby SH, Avery D, McDonald WM, Durkalski V, Pavlicova M, Holtzheimer PE (2010).Daily left prefrontal transcranial magnetic stimulation therapy for major depressive disorder: a sham-controlled randomized trial,Arch. General. Psychiatry, 67 (5), pp. 507–516  Perera T, George MS, Grammer G, Janicak PG, Pascual-Leone A, Wirecki TS.(2016) The clinical TMS society consensus review and treatment recommendations for TMS therapy for major depressive disorder. Brain Stimul. 9:336–46.  http://transcranialmagneticstimulation.com/  O’Reardon J. P., Solvason H. B., Janicak P. G., Sampson S., Isenberg K. E., Nahas Z., et al. . (2007). Efficacy and safety of transcranial magnetic stimulation in the acute treatment of major depression: a multisite randomized controlled trial. Biol. Psychiatry 62, 1208–1216.  http://www.tmscentereurope.com/treatment-depression-tms  Health Quality Ontario (2016). Repetitive transcranial magnetic stimulation for treatment-resistant depression: A systematic review and meta-analysis of randomized controlled trials. Ont Health Technol Assess Ser. 16:1–66.