For most people who benefit, TMS helps gradually over a four-to-six-week course of daily sessions rather than all at once. In one large trial analysis, about 1 in 5 people improved rapidly, about 7 in 10 improved steadily across the course, and about 1 in 10 did not respond. Some people only show a clear response near the end of the course, or after it.
That spread is why clinicians ask you to finish the course before judging it. Below is what the research shows about timing, what early signals do and do not tell you, whether TMS can make you feel worse first, and what to report along the way.
What "working" means
Clinicians use two milestones. Response usually means your depression score has dropped by at least half. Remission means the score has fallen below a cutoff where few symptoms remain; in the deep TMS pivotal trial, for example, that cutoff was a Hamilton score under 10. Many people notice partial improvement, such as better sleep or a little more energy, well before they reach either milestone. That partial change is worth reporting, because it is often the first sign that treatment is taking hold.
What the trials measured, and when
The major depression trials were built around a four-to-six-week window, so that is where the firmest evidence sits:
- The pivotal 2007 NeuroStar trial judged its main outcome at week 4.
- The deep TMS pivotal trial reported response and remission at week 5.
- The THREE-D trial treated people five days a week for four to six weeks.
A 2018 expert consensus advises telling patients that 20 to 30 sessions over six weeks will very likely be needed to match trial results. In a 2026 retrospective real-world study of people who had more than one TMS course, the median first session at which responders met response criteria in their first course was session 16 on one self-report scale (PHQ-9) and session 22.5 on another (BDI-II); on retreatment it came earlier, at session 12 and 13.5. In other words, a typical first-course responder had already had three to four weeks or more of treatment.
Four common patterns of response
A secondary analysis of the THREE-D trial (388 adults) modeled depression scores over the course and found four distinct trajectories.
| Pattern | Share of patients | What it looked like |
|---|---|---|
| Rapid response | 19% | Clear improvement early in the course |
| Steady improvement, higher starting symptoms | 30% | Gradual, roughly straight-line improvement |
| Steady improvement, lower starting symptoms | 40% | Gradual, roughly straight-line improvement |
| No response | 11% | Little change across the course |
Two points stand out. First, steady gradual improvement was the most common experience by far. Second, the pattern did not depend on whether people received standard 10 Hz TMS or theta-burst; it was linked to their own clinical features. Older age and not taking a benzodiazepine were associated with the rapid pattern, and higher starting severity with non-response. Our article on medications during TMS covers the benzodiazepine question.
Do early changes predict the outcome?
Somewhat, and this is one reason your team checks your scores at about the two-week mark.
- In a retrospective series of 101 patients treated at a dorsomedial prefrontal target (not the standard one) for 20 sessions, less than 20% improvement at session 10 correctly predicted non-response 88.2% of the time.
- In a naturalistic Australian sample of 117 patients, responders and non-responders had separated by session 10; the study did not follow scores past session 20, so it could have missed late responders.
- In a Swedish cohort of 136 patients, at least 20% improvement after two weeks predicted later response on a clinician rating.
The catch is accuracy. A 2026 pooled analysis of two theta-burst trials found that early improvement correctly predicted response 67–75% of the time (its positive predictive value), and the authors said that level is not good enough to justify stopping treatment. So a slow start is a reason to talk with your psychiatrist about the plan, not a reason to quit on your own.
Late responders: why finishing matters
Some people simply take longer. In a device-maker registry of 7,215 patients, those who received more than 36 sessions showed less improvement early in the course and a slower but steady climb, and extending treatment past 36 sessions was linked with further improvement without a clear plateau. The same registry found that courses shorter than 30 sessions had worse outcomes than longer ones. A registry of adolescents and young adults also found that longer courses produced greater improvement.
Registry data are open-label and cannot prove cause and effect, but they line up with the clinical advice: give the full course a fair chance. If you are partway through and unsure, read the week-by-week timeline to see where you are.
Can TMS make you feel worse before you feel better?
"Worse before better" was not one of the patterns seen in the THREE-D analysis: none of its four trajectories was an early dip followed by recovery. In a large registry of young people, fewer than 1% reported meaningful worsening on the PHQ-9.
That said, a few things can make the first week feel harder:
- Side effects. Scalp discomfort and headache are common early and usually fade; NeuroStar says scalp discomfort does not occur for most patients after the first week. Feeling sore and tired is not the same as depression getting worse, but tell the team either way.
- The daily logistics. Fitting in a visit every weekday is tiring on its own.
- Real worsening. Depression can worsen during any treatment. FDA's guidance for TMS devices asks manufacturers to include a prominent warning about worsening depression or suicidal thoughts. Mania or hypomania can occur, though in blinded trials its rate was not significantly different from sham.
If your mood drops, you feel unusually agitated, or you are sleeping much less with racing thoughts, call your psychiatrist the same day rather than waiting for the next scheduled rating. If you are thinking about suicide or are in crisis, call or text 988 (the 988 Suicide & Crisis Lifeline) or go to the nearest emergency room.
Accelerated TMS: fast schedule, not always fast results
Accelerated protocols compress many sessions into a few days, so it is natural to expect a faster effect. Sometimes that happens. In a 2026 company-sponsored head-to-head trial of deep TMS (104 adults), the accelerated schedule reached remission in 21 days versus 28 days for the standard schedule. But benefit can also show up after the treatment days end. FDA's SAINT summary notes that effectiveness was evaluated four weeks after treatment. In a small 2026 retrospective study of a five-day accelerated schedule (40 people), the half of patients who had not improved by day 5 went on to improve 36% at the two-to-four-week follow-up. If you have an accelerated course, ask when your follow-up rating will be, and do not judge the result on the last treatment day. Dr. Lewis's physician guide explains the protocols in accelerated TMS: protocols and evidence.
Why some people seem to respond to "nothing"
In sham-controlled TMS trials, people receiving the placebo coil often improve too; a meta-analysis of 61 trials found a large average improvement with sham. That does not mean active TMS is a placebo; active treatment outperformed sham in pivotal trials such as OPT-TMS, though not in every trial. It does mean that early ups and downs over a few days are hard to read. Trends across several weeks of ratings tell you more than any single day.
What to track and tell your clinician
You will fill out formal scales, but your own notes help your psychiatrist interpret them. Each week, jot down:
- Your mood on most days, on a simple 0–10 scale.
- Sleep: hours, and whether you wake early.
- Energy, interest and ability to get things done.
- Side effects and how long they last after a session.
- Any medication change, missed session, illness, alcohol or late night.
- Anything worrying: worse mood, agitation, very little sleep, thoughts of self-harm.
Our guide to tracking progress with the PHQ-9 and other scales explains how scores are read. If the course ends without a clear benefit, what to do if TMS does not work lays out the next options.
For the bigger picture, start at the TMS guide or visit the TMS therapy page.
Sources
- Efficacy and safety of transcranial magnetic stimulation in the acute treatment of major depression: a multisite randomized controlled trial. Biological Psychiatry, 2007. pubmed.ncbi.nlm.nih.gov
- Efficacy and safety of deep transcranial magnetic stimulation for major depression: a prospective multicenter randomized controlled trial. World Psychiatry, 2015. pmc.ncbi.nlm.nih.gov
- Effectiveness of theta burst versus high-frequency repetitive transcranial magnetic stimulation in patients with depression (THREE-D): a randomised non-inferiority trial. The Lancet, 2018. pubmed.ncbi.nlm.nih.gov
- Consensus Recommendations for the Clinical Application of Repetitive Transcranial Magnetic Stimulation (rTMS) in the Treatment of Depression. Journal of Clinical Psychiatry, 2018. pmc.ncbi.nlm.nih.gov
- Transcranial Magnetic Stimulation Retreatment for Recurrent Depression: A Large Real-World Multisite Cohort Study. Acta Psychiatrica Scandinavica, 2026. pubmed.ncbi.nlm.nih.gov
- The Effectiveness of Transcranial Magnetic Stimulation in Adolescents and Young Adults With Major Depressive Disorder. JAACAP Open, 2025. pubmed.ncbi.nlm.nih.gov
- Safety Information. NeuroStar (Neuronetics), 2026. neurostar.com
- Class II Special Controls Guidance Document: Repetitive Transcranial Magnetic Stimulation (rTMS) Systems. U.S. FDA, 2011. fda.gov
- Hypomanic/manic switch after transcranial magnetic stimulation in mood disorders: A systematic review and meta-analysis. World Journal of Psychiatry, 2021. europepmc.org
- Accelerated TMS with the H1-coil for depression: A multisite, randomized non-inferiority trial. Brain Stimulation, 2026. pubmed.ncbi.nlm.nih.gov
- K220177 510(k) Summary - Magnus Neuromodulation System with SAINT Technology. U.S. FDA, 2022. accessdata.fda.gov
- A systematic review and meta-analysis on placebo response to repetitive transcranial magnetic stimulation for depression trials. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 2018. pubmed.ncbi.nlm.nih.gov
- Trajectories of Response to Dorsolateral Prefrontal rTMS in Major Depression: A THREE-D Study. American Journal of Psychiatry, 2019. pubmed.ncbi.nlm.nih.gov
- Early symptom improvement at 10 sessions as a predictor of rTMS treatment outcome in major depression. Brain Stimulation, 2018. pubmed.ncbi.nlm.nih.gov
- Repetitive transcranial magnetic stimulation: Course and early prediction of response in depression. Journal of Psychiatric Research, 2023. pubmed.ncbi.nlm.nih.gov
- Early symptom improvement and other clinical predictors of response to repetitive transcranial magnetic stimulation for depression. Journal of Affective Disorders, 2024. pubmed.ncbi.nlm.nih.gov
- Dose or time? Comparing early prediction of intermittent theta-burst stimulation response across accelerated and daily protocols for depression. European Archives of Psychiatry and Clinical Neuroscience, 2026. pubmed.ncbi.nlm.nih.gov
- Dosing transcranial magnetic stimulation in major depressive disorder: Relations between number of treatment sessions and effectiveness in a large patient registry. Brain Stimulation, 2023. pubmed.ncbi.nlm.nih.gov
- Efficacy of 5 x 5 accelerated versus conventional repetitive transcranial magnetic stimulation (rTMS) for treatment-resistant depression. Journal of Affective Disorders, 2026. pubmed.ncbi.nlm.nih.gov
- Effect of Repetitive Transcranial Magnetic Stimulation on Treatment-Resistant Major Depression in US Veterans: A Randomized Clinical Trial. JAMA Psychiatry, 2018. pubmed.ncbi.nlm.nih.gov
- Daily left prefrontal transcranial magnetic stimulation therapy for major depressive disorder: a sham-controlled randomized trial. Archives of General Psychiatry, 2010. pubmed.ncbi.nlm.nih.gov
FAQs
How many sessions before TMS starts working?
There is no single number. In one real-world study, people who responded to a first course first met response criteria at a median of session 16 to 22.5, depending on the rating scale, and some people take longer.
If I feel nothing after two weeks, should I stop?
No, not on your own. Early improvement is only a rough predictor, and some people respond late. Talk with your psychiatrist about whether to continue, adjust or extend.
Does theta-burst work faster than standard TMS?
Theta-burst sessions are much shorter, but in the THREE-D analysis the pattern of improvement over the course did not differ between theta-burst and standard 10 Hz TMS.
Can improvement continue after the last session?
It can, especially after accelerated schedules, which is why follow-up ratings a few weeks later matter. How long benefit lasts is covered in our maintenance guide.
Is it normal to have good days and bad days during TMS?
Yes. Day-to-day swings are common in depression with any treatment. Look at the trend across weeks, and report any sharp or sustained worsening right away.
