What Are the Side Effects of TMS? – Achieve TMS East

What Are the Side Effects of TMS?

Transcranial magnetic stimulation (TMS) is a non-invasive treatment approved for major depressive disorder and obsessive-compulsive disorder, particularly in patients who do not respond to first line treatment methods (pharmacology and therapy). If a patient does not experience relief from their depression symptoms despite trying several different medications, they may be diagnosed with ‘treatment-resistant depression’.

TMS utilizes magnetic waves directed at a portion of a patient’s brain through a specialized helmet, stimulating the cells in that area to reduce depressive symptoms. TMS is painless, requires no medication or anesthesia, and no surgery. Sessions last less than half an hour and are performed several times a week for up to six weeks, depending on a patient’s symptoms and treatment plan.

TMS has shown to be particularly effective for patients with treatment-resistant depression. However, because the treatment utilizes a device directing magnetic waves directly at a portion of a patient’s brain, some patients worry about potential side effects. Despite the somewhat alarming name, TMS is completely safe and has no lasting side effects. Mild side effects can occur, but are increasingly rare, and fade soon after a treatment session ends. These may include:


Mild Headaches

Some patients have reported experiencing mild headaches during or shortly after TMS treatment. The headaches are reported to go away after a session, and their frequency often decreases with subsequent sessions. These are mild headaches, and as such are often treated with over-the-counter pain relief.

Note that while TMS technology is also used to treat migraine, migraine and headaches are two different things. However, specific TMS treatments have also been used to treat headaches. Headaches associated with TMS treatment may be caused by general physical discomfort with the placement of the coil or helmet, both of which may be adjusted during the treatment process for more comfort without compromising the effectiveness of the treatment.


Scalp Sensations

Up to a third of patients, by some estimates, report sensations on the scalp ranging from uncomfortable to mildly painful. These go away over the course of a treatment plan, as a patient adjusts to the sensation of TMS, and after certain adjustments are made following a first session. Some patients report a tapping sensation, while others report a prickling sensation.


Facial Twitching

Because TMS utilizes magnetic waves to stimulate portions of the brain, an unintended side-effect may be mild facial twitching due to the stimulation. These are harmless, and nothing to worry about aside from the discomfort they may produce during the procedure. Like the initial discomfort on the scalp, these too seem to be reduced over subsequent treatment sessions.


Hearing Issues

For patients with sensitive hearing, earplugs may be used to drown out the loud noise of the TMS machine, which some might consider distressing or potentially painful. However, rather than being a side-effect of the treatment itself, this is usually rather an issue with the TMS machine being too loud for some patients.

Simply wearing earplugs is often enough to reduce the discomfort by muffling the noise, thereby effectively eliminating the danger of damage to a patient’s hearing.



TMS and dTMS (deep transcranial magnetic stimulation) treatments have also reported rare cases of dizziness after a session. Lightheadedness may accompany the dizziness, but both symptoms resolve shortly after the session. While it may be safe for most patients to drive after a TMS session, it would be wiser to ask someone to pick you up if you feel dizzy/nauseous/lightheaded after a session.

Overall, these symptoms – alongside mild headaches – are the most common, but never severe. Most of these symptoms only occur within the first few sessions, decreasing over the four to six weeks during which the treatment takes place. Very few opt to stop treatment due to the discomfort.



Occurring in less than 0.01 percent of individuals (less than 1 in 10,000) during clinical trials, seizures are a rare risk associated with rTMS (repetitive transcranial magnetic stimulation), with studies showing it seems more common in conjunction with sleep deprivation, polypharmacy (utilizing several different medications), and neurological insult (birth-related nerve damage in the brain). These seizures leave no lasting effect on patients and are not considered a long-term adverse side effect. While this type of side effect is possible, it is exceedingly rare.

rTMS treatment facilities are trained and equipped to help patients who experience a seizure, and it is highly unlikely that a patient would experience one during or after treatment. A systematic review of TMS-related studies from 1980 to 2015 revealed 25 instances of rTMS-induced seizures, excluding seizures related to specific conditions (such as epilepsy).


TMS and Metal

Because transcranial magnetic stimulation involves the use of magnetic fields to stimulate the brain, patients with conductive metallic objects in or around their head are not to be treated using TMS technology. Examples of non-removable conductive metal include:

  • Shrapnel/bullet fragments
  • Tattoos with magnetic-sensitive ink
  • Metallic implants/medical magnetic-sensitive implants
  • Non-removable electrodes
  • Neuromodulation devices (vagus nerve stimulation devices, deep brain stimulation devices)
  • Stents in the neck
  • Aneurysm clips/coils
  • Other conductive metallic objects in/around the head

Transcranial magnetic stimulation is harmless to human tissue but can cause metal objects or devices to malfunction or heat up. Some metallic devices or objects are exceptions to this, because they do not react to the magnetic waves. These include braces and dental fillings. Be certain to go over your medical history with a TMS provider before opting for TMS treatment.

While there are a number of possible and documented side effects when considering TMS treatment, these side effects are increasingly rare. The most common complaint is a slight tapping sensation or prickling on the scalp, with the other occasional issue being irregular headaches shortly after a session. These sensations and headaches, however, pass very quickly after a session and have no lasting effect on a patient.

Furthermore, research shows that TMS treatment has no negative effect on a patient’s cognition. While TMS can potentially affect the release of serotonin, it does not share the side effects commonly experienced when using antidepressant medication. TMS’ side effects do not show lasting repercussions, making it an effective alternative for the treatment of major depressive disorder in patients who do not respond to first line treatments. You can also check out real patient reviews to see what actual patients think of the process to help you make an informed decision about your treatment.


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