The side effects of TMS are remarkably few – and cause little overall discomfort for most patients.

• The main risk of TMS is inducing a seizure, though with close monitoring this complication has been very rare. No seizures have been reported in the scientific literature since safety guidelines were implemented in 1996.
  

• Since the brain is directly stimulated by TMS, there is a potential risk of disturbing its normal functions. But so far, neither cognitive side-effects such as loss of memory, nor changes in concentration or other cognitive capacities have been reported.

• About one patient in ten experiences a headache caused by muscle stimulation as the magnetic pulses pass through the scalp.  Such headaches usually pass after a few hours or on taking some mild analgesic medicine.

• Some patients also experience mild to moderate scalp discomfort at the stimulation site during the first week of treatment. This typically subsides as the patient gets used to the treatment. Lastly, some experience a slight twitching of the jaw muscles during treatment.

In contrast, the side effects of the most widely used anti-depressant drugs are far more extensive.