Transcranial magnetic stimulation (TMS) is a very well tolerated treatment, with only a few TMS side effects. As a depression treatment, TMS has been used to treat thousands of people.
In fact, more than 80% of patients adhere to TMS treatment, which means they complete all the prescribed treatment sessions. This is much higher than for antidepressants. One of the main reasons why patients complete all their TMS treatment sessions is because it is very safe and tolerable.
What are the main TMS side effects?
Many clinical trials have been conducted to study TMS treatment. Three of the major trials in adults with depression compared TMS treatment with a sham TMS treatment (where everything was the same except no magnetic pulses were applied). None of the 703 patients or the clinicians giving the treatment knew whether the patient received the TMS treatment to make sure the results, including how well the treatment worked and the side effects were real.
From these studies, the main TMS side effects were:
|Primary TMS side effects||Drug side effects|
|Scalp discomfort||Dry mouth|
|Mild headache||Fatigue or sedation|
Scalp discomfort can be a side effect of TMS treatment. The discomfort is usually minor and often only occurs in the first few TMS sessions. It is very rare for a patient to request the treatment be stopped. The discomfort usually occurs where the TMS machine is placed on the scalp.
Mild headache is one of the most common TMS side effects. In 3 large clinical trials that compared TMS treatment with a sham or inactive treatment, there was no difference in the number of people with headaches. If headaches are experienced during TMS treatment, they seem to occur less frequently as patients get used to the treatment.
Seizures are a potential side effect of TMS treatment. It is very unlikely that a seizure will occur during or after treatment and patients are screened to ensure they are not at a high risk. The seizures that have occurred were during a TMS treatment session and were short and self-limited. The chance of having a seizure during a TMS session is lower than the chance of having a seizure while taking antidepressants.
Who should not receive TMS?
People who should not receive TMS included those with a history of seizure or those with metal implants in their head. Tooth fillings are ok and carry no risk. A psychiatrist with expertise in TMS should perform a thorough assessment of each patient prior to treatment to ensure they are suitable. It is also important that patients are monitored during every treatment session and any side effects are managed.
- Australian depression treatment guidelines
- TMS a Drug-free depression treatment
- How to treat severe depression
- How antidepressants work
- Carpenter L et al. Transcranial magnetic stimulation (TMS) for major depression: a multisite, naturalistic, observations study of acute treatment outcomes in clinical practice. Depression and Anxiety 2012; 29: 587-596.
- Dobek CE et al. Risk of seizures in transcranial magnetic stimulation: a clinical review to inform consent process focused on bupropion. Neuropsychiatric Disease and Treatment 2015; 11: 2975–2987.
- George MS et al. Daily left prefrontal transcranial magnetic stimulation therapy for major depressive disorder. Arch Gen Psychiatry. 2010; 67: 507-516.
- Levkovitz Y et al. Efficacy and safety of deep transcranial magnetic stimulation for major depression: a prospective multicenter randomized controlled trial. World Psychiatry 2015; 14: 64–73.
- O’Reardon JP et al. Efficacy and safety of transcranial magnetic stimulation in the acute treatment of major depression: a multisite randomized controlled trial. Biol Psychiatry 2007; 62: 1208–1216.
- Royal Australian and New Zealand College of Psychiatrists. Position Statement 79: Repetitive transcranial magnetic stimulation.