How well does TMS actually work for depression?
TMS is a non-invasive treatment that uses magnetic pulses to stimulate nerve cells in brain regions linked to mood, most commonly the left dorsolateral prefrontal cortex. The strongest evidence comes from a meta-analysis of 12 sham-controlled trials, which found a statistically significant overall effect size of 0.81 [3]. An effect size of 0.8 is considered large, meaning the average person receiving TMS did better than about 79% of those receiving a sham (placebo) treatment. However, the same analysis noted that the clinical significance was modest: only 13.7% of patients responded (a 50% drop in depression scores) with TMS versus 7.9% with sham [3]. This tells you TMS is a real, effective tool, but it's not a home run for everyone.
A more recent large randomized trial (240 patients) compared TMS alone, transcranial direct current stimulation (tDCS) alone, the two combined, and a sham group. After two weeks, the combined group showed an average 18-point drop on the Hamilton Depression Rating Scale, compared to about 15 points for TMS alone, 9 for tDCS alone, and 11 for sham [1]. This suggests TMS works, and combining it with another brain stimulation method may boost results.
Who benefits most? What about treatment-resistant depression?
TMS is particularly valuable for people with treatment-resistant depression (TRD)—those who haven't gotten better with medication. A double-blind crossover study of 38 TRD patients found that adding TMS to their existing medication led to a 63% response rate and a 42% remission rate [6]. This means nearly two-thirds of people who had failed other treatments got significantly better, and over 40% became symptom-free. The same study also found TMS significantly reduced anxiety symptoms [6], which is a common and debilitating companion to depression.
Interestingly, deep TMS (using a different coil that reaches deeper brain areas) may be especially effective for people with anxious depression. A pooled analysis of trials found an effect size of 0.55 for reducing anxiety, and unlike with medication or standard TMS, higher baseline anxiety actually predicted a better outcome with deep TMS [2]. So if you have depression with significant anxiety, deep TMS might be a particularly good fit.
For postpartum depression, a study of 152 women found that combining the antidepressant sertraline with TMS produced a 95.6% effectiveness rate after 8 weeks, compared to 78.7% with sertraline alone [4]. The combined group also showed greater improvements in quality of life and hormone levels, without more side effects.
What about newer, faster TMS protocols?
Traditional TMS requires daily sessions for 4–6 weeks, which can be a major time commitment. A major breakthrough is the FDA-cleared SAINT protocol, which uses functional MRI to precisely target the brain region and delivers multiple sessions per day for just five days. In a randomized trial of 29 adults with treatment-resistant depression, the SAINT group experienced a 62% average reduction in depression scores after five days, compared to a 14% reduction with sham [5]. At four weeks, 69% had responded and 46% were in remission [5]. This is dramatically better than the older protocols, though experts note these results need replication in larger, more diverse groups [5].
A meta-analysis of 30 trials confirmed that more TMS sessions produce better results: 20 sessions yielded a much larger effect (effect size -2.74) than 5 sessions (effect size -0.43) [7]. So if you're considering TMS, committing to a full course matters. The same analysis found that 1200–1500 pulses per session seemed to be the sweet spot for effectiveness [7].
Sources used in this answer
Transcranial Direct Current Stimulation Combined With Repetitive Transcranial Magnetic Stimulation for Depression
Combining TMS with tDCS was more effective than either alone or sham, with an 18-point drop on the Hamilton Depression Rating Scale after 2 weeks (vs. 15 for TMS alone) [1].
Efficacy of Deep TMS with the H1 Coil for Anxious Depression
Deep TMS effectively treats comorbid anxiety in depression, with a pooled effect size of 0.55; higher baseline anxiety predicted better outcomes, unlike with standard treatments [2].
A Meta-analysis of Repetitive Transcranial Magnetic Stimulation in the Treatment of Depression
Meta-analysis of 12 studies found TMS superior to sham with a moderate-to-large effect size (0.81), but only 13.7% of patients responded vs. 7.9% with sham [3].
Sertraline plus repetitive transcranial magnetic stimulation for the treatment of postpartum depression.
Combining sertraline with TMS for postpartum depression yielded a 95.6% effectiveness rate after 8 weeks, vs. 78.7% for sertraline alone [6].
FDA Clears Accelerated TMS Protocol for Depression
The FDA-cleared SAINT accelerated TMS protocol produced a 62% reduction in depression scores after 5 days, with 69% response and 46% remission at 4 weeks [7].
Efficacy of transcranial magnetic stimulation in treatment-resistant depression
In 38 treatment-resistant depression patients, adding TMS to medication led to a 63% response rate and 42% remission rate, with significant anxiety reduction [8].
High-frequency repetitive transcranial magnetic stimulation over the left DLPFC for major depression: Session-dependent efficacy: A meta-analysis.
Meta-analysis of 30 trials found more TMS sessions produce larger effects; 20 sessions (effect size -2.74) outperformed 5 sessions (-0.43), with 1200-1500 pulses per session optimal [11].