Transcranial Magnetic Stimulation (TMS) therapy was first approved by the FDA for treatment of treatment resistant depression back in 2008. TMS therapy utilizes a computerized, electromechanical device to deliver non-invasive, brief magnetic stimulation pulses to discrete cortical regions and associated neural circuits. The peak magnetic field strength is comparable to a typical magnetic resonance imaging (MRI) device, with the only difference being that while the MRI field is large and constantly on, the TMS magnetic fields are focal and brief.
Although the rates of response and remission are variable in studies involving TMS, TMS continually outperforms the control/placebo groups. In one such study, they demonstrated TMS therapy to be 3 times more likely to remit patients than those in the control/placebo condition. In another such study, they were able to demonstrate that TMS therapy was able to remit 30% of patients while most patients who are treatment resistant have a 10-20% chance of responding to another medication or treatment method following a failed antidepressant trial. Together, this makes TMS therapy an appealing treatment method for those who have failed to respond to antidepressants in the past.
As far as side effects, TMS therapy is considered to be relatively safe. Some common side effects include headaches, site discomfort and facial twitching. In some cases, vasovagal syncope (sudden drop in heart rate and blood pressure leading to fainting) has occurred, but can be managed with reassurance and protection from hard. In extreme cases, seizures are also a safety risk associated with TMS, however the incident of seizure with TMS is small and appears slightly less than the incident risk for seizures with current antidepressant medications (overall risk of seizures in TMS sessions is estimated to be less than 1 in 30,000, <0.003%).
The standard treatment for TMS involves five daily treatments repeated for 4-6 weeks. Some slow patients who respond slowly to TMS may benefit from an additional 1-4 weeks, while others may respond to 12 weeks of twice weekly sessions following the initial 4-6 weeks. Treatment using TMS is individual and personal, and treatment plans should be carefully considered with your physician.
So who is TMS therapy for?
According to the clinical recommendations in this article, TMS therapy is recommended to adults who
Present with a clinical diagnosis consistent with the DSM-5 defined MDD, and for whom antidepressant medication has not provided a satisfactory clinical benefit, or for whom intolerance to medications precludes their use
Previously benefited from an acute treatment course and are experiencing a recurrence of their illness
May or may not be currently using antidepressants or other psychotropic medications. There is currently no data to support the use of medication with TMS, but there is also no evidence of an increased risk of adverse events by combining medication with TMS
Benefitted from the acute course of treatment. Continuation or maintenance treatments may be considered for these patients.
Are relapsing back into depression following an initial response to TMS therapy
Sources:
“The Clinical TMS Society Consensus Review and Treatment Recommendations for TMS Therapy for Major Depressive Disorder.” Brain Stimulation, Elsevier, 16 Mar. 2016, www.sciencedirect.com/science/article/pii/S1935861X16300389.
George, Mark S., et al. “Daily Left Prefrontal Transcranial Magnetic Stimulation Therapy for Major Depressive Disorder.” Jama Network, jamanetwork.com/journals/jamapsychiatry/article-abstract/210744. Accessed 12 Feb. 2024.