TMS can be used for seasonal (winter) depression when it meets the criteria for major depressive disorder, because TMS is FDA-cleared for major depression in adults that has not improved with antidepressant medication in the current episode. What is missing is research built around the seasonal pattern itself: there is no FDA clearance specific to seasonal affective disorder (SAD), and the main study we found is one retrospective, open-label analysis.
For most people with winter depression, light therapy, a seasonal version of CBT or medication comes first. TMS is a later option for winter episodes that have not responded to those.
Seasonal depression is major depression with a pattern
The National Institute of Mental Health describes SAD as "a type of depression characterized by a recurrent seasonal pattern." To be diagnosed, a person needs depressive episodes in a particular season for at least two consecutive years, and those seasonal episodes must outnumber episodes at other times of year. Symptoms typically last four to five months.
In other words, SAD is not a separate illness from depression. It is depression that keeps returning on a schedule, most often in fall and winter. That is why TMS's depression clearance can apply. Our pages on what TMS is and what is FDA-cleared explain the label in full.
NIMH notes that SAD is more common in people with bipolar disorder, especially bipolar II disorder, which involves depressive episodes and hypomanic episodes. That distinction matters before any treatment, TMS included, and is one reason a careful history comes first.
What the research says about TMS and seasonal pattern
Evidence specific to winter depression is thin. In a 2023 retrospective study of 127 people with major depression treated with open-label high-frequency TMS, 46% (58 people) had a seasonal pattern on a screening questionnaire. Remission rates were similar with and without the seasonal pattern, 34% and 30%, and the difference was not significant. The authors concluded that seasonal depression appeared to respond to TMS about as well as non-seasonal depression.
That is encouraging but limited. The study was open-label, had no sham group, and grouped people by a questionnaire score rather than a formal SAD diagnosis. No randomized trial testing TMS specifically in seasonal depression turned up in our search of the medical literature in October 2026. So the best evidence for TMS in winter depression is really the general depression evidence, applied to people whose episodes happen to be seasonal.
The first-line options, and how they compare
NIMH lists four main treatments for SAD: light therapy, psychotherapy, antidepressant medication and vitamin D, used alone or together. All of them are easier to start than daily TMS visits.
| Option | How it is used | Evidence in seasonal depression |
|---|---|---|
| Bright light therapy | A 10,000-lux light box for about 30 to 45 minutes, usually in the morning, fall to spring | A 2020 meta-analysis of 19 randomized trials found it beat placebo, with moderate-to-high risk of bias in the studies |
| CBT for SAD (CBT-SAD) | Typically two group sessions a week for six weeks | In a 2015 randomized trial of 177 adults, remission on the clinician-rated SIGH-SAD scale was 47.6% with CBT-SAD and 47.2% with light therapy |
| Antidepressants | Taken alone or with therapy; usually take 4 to 8 weeks to work | FDA has approved extended-release bupropion, which can prevent recurrence when taken daily from fall into early spring |
| Vitamin D | Supplements, especially if levels are low | Study results have been mixed |
| TMS | Weekday sessions for about six weeks, plus a taper on some schedules | No seasonal-specific trial; one retrospective study found similar remission with and without a seasonal pattern |
Light therapy and CBT-SAD are the most specific to the seasonal pattern. Our articles on CBT for seasonal affective disorder and integrative options for SAD go deeper into both.
Winter blues, SAD or something else?
Feeling slower and less social when the days get short is common, and it is not the same as seasonal depression. The difference is degree and impact. NIMH lists symptoms typical of winter-pattern SAD: oversleeping, overeating with carbohydrate cravings and weight gain, and social withdrawal that feels like hibernating, on top of the usual symptoms of depression. When those symptoms make work, parenting or relationships hard for weeks at a time, it is worth an evaluation rather than waiting for spring.
A few other things can look like winter depression and deserve a check first:
- Thyroid problems, anemia and low vitamin D, which a basic workup can find.
- Poor sleep, including sleep apnea, which worsens energy and mood in any season.
- Heavier drinking in the holiday months, which can drive low mood on its own.
- Grief that clusters around anniversaries or holidays.
Sorting these out is part of good care whichever treatment you choose, and it is also what a TMS team would look at before recommending a course. If you track your mood across a few seasons, bring that record; patterns over time are what make the diagnosis. Tracking your progress with the PHQ-9 shows a simple way to do it.
When TMS makes sense for winter depression
TMS becomes a reasonable conversation when:
- Your winter episodes meet criteria for major depression, and at least one antidepressant has not helped enough in the current episode.
- Light therapy, CBT or medication have been tried properly and have not worked, or medication side effects were not tolerable. See TMS after antidepressant side effects.
- Your depression is present year-round but worsens in winter, so the seasonal label is only part of the picture.
It is usually not the first move if you have never tried a light box or CBT-SAD, if your low mood is mild and short, or if there is any history of mania or hypomania that has not been assessed. Expert consensus also says people with psychotic symptoms or acute suicidal thoughts should be considered for treatments with established efficacy in those situations, such as ECT. The checklist in am I a candidate for TMS covers the rest.
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.
Timing a course before the dark months
If you and your psychiatrist decide on TMS, timing becomes practical. One cleared schedule runs 5 days a week for 6 weeks, then tapers over 3 more weeks, for 36 sessions. Add the consultation and, if you use insurance, prior authorization, and the whole process can stretch over several months.
NIMH notes that people with a history of SAD "might benefit from starting the treatments mentioned above before the fall", while also noting that few studies have tested prevention. That advice is about light, therapy, medication and vitamin D. Nobody has tested TMS given before symptoms start as a way to prevent a winter episode, and insurance criteria are written for a current episode, not a predicted one. A realistic plan looks more like this:
- Late summer: review last winter with your psychiatrist and restart whatever helped.
- Early fall: if symptoms return despite first-line treatment, book a TMS consultation and gather your medication history.
- As soon as criteria are met: start the paperwork. TMS prior authorization explains the steps.
- Plan travel for the darkest weeks; daily visits in snow and early sunsets are harder than they sound.
What about next winter?
Seasonal depression tends to come back, so the question after a good TMS response is how to stay well. Maintenance TMS is "promising", but the right frequency is unclear, and most insurers do not cover it. Many people instead keep a light box, a CBT plan or a fall medication strategy in place and treat early if symptoms return. TMS maintenance sessions covers the options, and the TMS guide lists every related topic. To talk through your own winter pattern, start with TMS therapy.
Sources
- 510(k) K160703 - NeuroStar TMS Therapy System. U.S. Food and Drug Administration, 2016. accessdata.fda.gov
- Seasonal Affective Disorder (NIH Publication No. 23-MH-8138). National Institute of Mental Health, 2023. nimh.nih.gov
- Seasonal pattern and depression outcomes from repetitive transcranial magnetic stimulation. Psychiatry Research, 2023. pubmed.ncbi.nlm.nih.gov
- The Efficacy of Light Therapy in the Treatment of Seasonal Affective Disorder: A Meta-Analysis of Randomized Controlled Trials. Psychotherapy and Psychosomatics, 2020. pubmed.ncbi.nlm.nih.gov
- Randomized Trial of Cognitive-Behavioral Therapy Versus Light Therapy for Seasonal Affective Disorder: Acute Outcomes. American Journal of Psychiatry, 2015. pubmed.ncbi.nlm.nih.gov
- K231926 510(k) Summary - NeuroStar Advanced Therapy System. U.S. Food and Drug Administration, 2024. accessdata.fda.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, LCD L33398 (version 40). Centers for Medicare & Medicaid Services, 2026. cms.gov
- Consensus review and considerations on TMS to treat depression: A comprehensive update endorsed by the National Network of Depression Centers, the Clinical TMS Society, and the International Federation of Clinical Neurophysiology. Clinical Neurophysiology, 2025. tmslab.org
FAQs
Is TMS FDA-cleared for seasonal affective disorder?
Not as a separate condition. TMS is cleared for major depression that has not improved with medication, and seasonal depression is major depression with a recurring seasonal pattern.
Can I use a light box during a TMS course?
Light therapy and TMS have not been studied together for seasonal depression. Many people keep using their light box, but agree it with your psychiatrist so changes in mood can be tracked clearly.
Does summer depression count?
A seasonal pattern can occur in any season, though fall and winter onset is most common. The same rule applies: TMS evaluation depends on whether the episode meets criteria for major depression.
Will one TMS course stop SAD from coming back?
There is no evidence that it prevents future winters. Planning ahead with light therapy, CBT or medication, and treating early, is the usual approach.
