The risks of TMS are relatively low because the procedure is noninvasive—it does not require anesthesia or the implantation of electrodes. The treatment can take place in a doctor’s office and patients are able to drive themselves home after the procedure. Side effects from the treatment can include facial spasms or tingling, lightheadedness, headaches, and scalp discomfort where the stimulation is applied.
While TMS is a safer and less invasive alternative to other brain stimulation procedures, there are certain risks associated with any type of treatment. Most patients undergo TMS with no major side effects.
With more than 10,000 treatments performed in clinical trials, the most common side effect associated with TMS Therapy was mild-moderate scalp discomfort. Other common side effects included minor twitching around the eye; minor twitching of facial muscles; toothache; and mild-moderate headache. Side effects usually resolve by end of each treatment session period. These too tend to diminish over the course of treatment although adjustments can be made immediately in coil positioning and settings to reduce any discomfort. There is a rare risk of seizure associated with TMS Therapy (less than 1 in 30,000).
TMS is well-tolerated and associated with few side-effects and only a small percentage of patients discontinue treatment because of these. The most common side-effect, which is reported in about half of patients treated with TMS, is headaches. These are mild and generally diminish over the course of the treatment. Over-the-counter pain medication can be used to treat these headaches. The TMS machine produces a loud noise and because of this, earplugs are given to the patient to use during the treatment.
TMS has not been associated with many of the side-effects caused by antidepressant medications, such as gastrointestinal upset, dry mouth, sexual dysfunction, weight gain, or sedation.
After a full course of treatment, patients notice a significant reduction in symptoms which persists beyond the end of the treatment course.
Approximately 60% of people with depression who have tried and failed to receive benefit from medications experience a clinically meaningful response with TMS. About one-third of these individuals experience a full remission, meaning that their symptoms go away completely. It is important to acknowledge that these results while encouraging, are not permanent. Like most other treatments for mood disorders, there is a high recurrence rate. However, most TMS patients feel better for many months after treatment stops, with the average length of response being a little more than a year. Some will opt to come back for subsequent rounds of treatment.