The effectiveness of TMS therapy
The success rate matters to anyone considering TMS for depression. TMS is a medical treatment, and nothing in medicine works for everyone. A few points help put the numbers in context.
- The headline numbers come from randomized controlled trials. Patients did not know whether they received real stimulation or a sham, which lowers the response rate compared with real-life practice.
- Patients in clinical trials usually have severe, resistant depression and have already tried several medications.
- Response rates compare well with repeated antidepressant trials, where the chance of improving falls with each new medication.
- TMS technology keeps improving, including navigated and accelerated protocols.
Read the transcript
What is the success rate of TMS therapy? Your chance of responding to TMS therapy is 58%. If we compare TMS therapy with antidepressant medications, that number becomes very impressive.
Your chance of responding to the first antidepressant is about 27%. If you do not respond and we go to the second one, it goes down to 21%. When we go to the third one, it is 16%. By the time we go to the fourth antidepressant medication, your chance of responding to that medicine is only 6.9%.
If we take that patient and treat them with TMS therapy, they have a 58% response rate. That is significant compared with 6.9%, and that is without using any medications.
How effective is TMS?
The pivotal randomized trial submitted to the FDA in 2007 found that 58% of patients responded and 37% reached remission after about 30 treatment sessions. An NIH-sponsored trial in 2010 reported a similar outcome, and other trials have since replicated these findings. In randomized trials, response rates range from roughly half to two-thirds of patients.
Open-label studies, where patients know they are receiving TMS, tend to show higher response rates. Accelerated TMS protocols have also shown high response rates in published research, including in treatment-resistant depression.
Is TMS FDA-cleared?
- Major Depressive Disorder in adults who have not improved enough with prior antidepressant medication, cleared in 2008
- Obsessive-Compulsive Disorder in adults, cleared in 2018
- Anxious depression (MDD with anxiety symptoms), cleared in 2021
If TMS works so well, why is it not tried before medication?
A more expensive treatment is usually reserved for second-line use. The first trials in 2007 enrolled patients who had failed one or more antidepressants, so the FDA cleared TMS on that data. This does not mean TMS cannot help earlier.
How long do the effects of TMS last?
Studies suggest that about two thirds of patients who respond keep their improvement for six to twelve months after treatment, and some stay well much longer. Depression can return in some patients, which is why follow-up matters.
After a good response we usually recommend a short taper of sessions over about three weeks, since this may help delay a relapse. If symptoms return two months or more after treatment, a repeat course of TMS is often an option. If they return sooner, we discuss other treatments such as Spravato®.
Read the transcript
How long does the effect of TMS therapy last? Based on what has been published and researched so far, about two out of three patients maintain their response six to 12 months after treatment. One-third of patients may have a recurrent depressive episode six to 12 months after treatment.
The good news is that patients who have a recurrent depressive episode have a very high chance of responding to TMS again.
Evidence for ongoing maintenance sessions is not conclusive, and insurance generally does not cover them. Your doctor will advise you on what makes sense.
References
- 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(11):1208-16.
- George MS et al. Daily left prefrontal transcranial magnetic stimulation therapy for major depressive disorder: a sham-controlled randomized trial. Arch Gen Psychiatry. 2010;67(5):507-16.
Frequently asked questions
Medical information on this page is educational and not a substitute for professional advice. Individual results vary.