Because TMS involves stimulating the brain, patients understandably ask about safety. Reassuringly, TMS
has an extensive safety record governed by
international consensus guidelines, and serious
adverse events are rare.
The seizure question
The most serious risk, a seizure, is very rare when established parameters are followed, historically estimated at well under one in thirty thousand sessions. Most of the few historical reports occurred before safety limits were formalised or when those limits were exceeded; adhering to the guidelines has all but eliminated inadvertent seizures in modern practice.
Common, mild effects
The usual side effects are mild and temporary: scalp discomfort at the stimulation site and headache, which tend to ease over the first week and respond to simple pain relief. Unlike ECT, TMS needs no anaesthesia and is not associated with memory loss.
Who needs caution
The main contraindication is ferromagnetic metal or an active implanted electronic device, such as a cochlear implant or certain aneurysm clips, near the coil. A history of epilepsy or other seizure-lowering factors warrants careful assessment first, which is why every patient is screened.
With modern parameters and proper screening, TMS is well tolerated. Its most common effects are temporary scalp discomfort and headache, and its most serious risk, a seizure, is extremely rare.
References
- Rossi S, et al. (2009). Safety, ethical considerations, and application guidelines for the use of TMS. Clinical Neurophysiology.
- O'Reardon JP, et al. (2007). Biological Psychiatry (side-effect reporting).
This article is for general information and is not medical advice. TMS suitability is decided by a psychiatrist on an individual basis. Speak to our team about your own situation.