TMS for depression is not known to harm memory or thinking. A systematic review of 31 randomized controlled studies of prefrontal TMS found no reliable evidence of cognitive side effects, and cognitive function did not change in the NeuroStar development program. Unlike ECT, TMS does not involve anesthesia or an induced seizure, and memory loss is not one of its recognized side effects.
What some people do notice is tiredness, a headache or feeling a bit "off" on treatment days, mostly early in a course. Whether TMS actively sharpens memory or concentration is less clear: the studies disagree. (Using TMS to treat memory disorders such as Alzheimer's disease is a separate, research-stage question and is not FDA-authorized.)
What the research shows
Three kinds of evidence point the same way:
- Randomized trials, pooled. The 2021 international safety guidelines (IFCN) cite a review of 31 randomized controlled studies of rTMS to the dorsolateral prefrontal cortex in depression, schizophrenia or Alzheimer's disease that found no reliable evidence of cognitive side effects.
- Device safety programs. In the NeuroStar development program, covering 325 patients and more than 10,000 sessions, auditory threshold and cognitive function did not change.
- Intensive protocols. Even with the accelerated SAINT protocol, 10 sessions a day for 5 days, neuropsychological testing in the open-label study showed no negative cognitive effects.
This is reassuring, but it is worth being precise about what it covers. These studies measure thinking skills with standard tests over weeks to months. They were not designed to catch very rare or individual effects, and long-term follow-up is thinner than for short-term outcomes.
TMS vs ECT: why memory comes up
Many people ask about memory because they have heard about ECT (electroconvulsive therapy). ECT is a highly effective treatment, but it works through a brief seizure under general anesthesia, and memory effects are a well-documented trade-off.
| TMS | ECT | |
|---|---|---|
| Anesthesia | None; you are awake | General anesthesia each session |
| Short-term thinking | No reliable cognitive side effects in pooled trials | Cognitive effects mainly limited to the first 3 days after treatment in a large meta-analysis |
| Memory for past events | Not a recognized side effect | Persistent retrograde amnesia reported, more with bilateral and sine-wave ECT |
| Effectiveness | Lower than ECT overall in head-to-head meta-analyses | More effective overall, especially in psychotic depression |
The table draws on the IFCN guideline and on ECT and head-to-head meta-analyses. In a study of 347 patients at New York City-area facilities, adverse cognitive effects of ECT were still detectable 6 months after treatment, and bilateral ECT caused more severe and persistent loss of memory for past events than right unilateral ECT. A 2010 meta-analysis of 84 studies found that ECT's effects on objective test scores were mainly limited to the first 3 days, but it had no standardized tests of memory for past events, so it does not settle that question. In head-to-head trials, three studies suggested visual memory and verbal fluency were more impaired with ECT than with TMS.
This is a real trade-off, not a reason to rule out ECT. ECT is more effective overall, especially for psychotic depression, and the 2023 CANMAT guideline rates it first line for severe depressive episodes. 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. For the full comparison, see the physician's guide on drlewis.com to TMS vs ECT: effectiveness, memory and who each suits.
What people sometimes notice during TMS
Feeling a bit foggy or tired on a treatment day is not the same as memory damage, but it is worth knowing what is common:
- Fatigue. In the sham-controlled SAINT trial, an intensive 5-day protocol, 57% of the active group reported fatigue. Standard once-daily courses are much less intensive, and the daily travel itself can be tiring.
- Headache and scalp discomfort. These are the most common side effects and can make it harder to concentrate for a while after a session; they usually ease after the first week.
- Depression itself. Poor concentration, slowed thinking and forgetfulness are symptoms of depression, so early in a course it is often hard to tell what is causing what.
Reports to the FDA's adverse-event database are a different kind of signal. An analysis of 200 unique TMS reports through April 2025 found that 8.0% mentioned neurocognitive changes, but these reports are unverified and cannot tell us how often anything happens. If you notice a change in memory or thinking that worries you, tell your TMS team; it is useful information and should be checked rather than dismissed. Our guide to TMS side effects covers what to report and when.
Will TMS improve my memory or concentration?
Possibly, but mostly through treating the depression, and only as far as the evidence goes. Depression affects thinking: a meta-analysis using a standard test battery found moderate deficits in executive function, memory and attention in people with depression, and some deficits in executive function and attention persisted even after mood had improved.
Whether TMS improves thinking beyond lifting mood is unsettled. A 2025 meta-analysis of 15 sham-controlled trials in unipolar depression found no significant improvement with active TMS on any cognitive domain. Another 2025 meta-analysis of 23 trials of non-invasive brain stimulation found a small improvement in global cognitive function, including with TMS. The fair reading: do not choose TMS expecting a memory boost, but many people find that thinking feels clearer as depression eases. Tracking how you are doing helps; see tracking your progress during TMS.
How this compares with medication-based options
Some other treatments for hard-to-treat depression carry cognitive cautions of their own. The Spravato (esketamine) label warns that it may impair attention, judgment, thinking, reaction speed and motor skills, and says not to drive until the next day after a restful sleep. In the ELEKT-D trial, delayed-recall memory scores fell by 9.7 points with ECT vs 0.9 with IV ketamine at 3 weeks, with gradual recovery afterward. For a broader comparison, see TMS vs ketamine therapy.
Before you start: what to mention
A TMS evaluation includes a medical and neurological history, partly because some of the same conditions that affect thinking also affect TMS safety. FDA guidance asks for close monitoring of people with a history of seizures or epilepsy, stroke, head injury, other neurologic disease, or medications that lower the seizure threshold. Tell your psychiatrist if any of these apply, and also mention:
- any existing memory or concentration problems, and when they started, so there is a baseline
- past ECT, including how your memory was afterward
- hearing problems or ringing in the ears; TMS requires earplugs, and anyone who notices hearing loss, ringing or ear fullness after a session should be referred for a hearing check
- alcohol or other substance use, since withdrawal and some stimulants lower the seizure threshold
If you are over 60 and worried about memory, it is worth asking whether a cognitive screen makes sense before treatment; our article on TMS for older adults covers late-life depression in more detail.
Practical tips during a course
- Keep sleep regular; sleep loss affects both thinking and seizure threshold.
- Note any change in memory, hearing or concentration and mention it at your next session.
- Plan demanding tasks for the time of day you feel sharpest, especially in the first week.
- If you have had ECT before, tell your TMS team about any lasting memory effects so they have a baseline.
Most people can keep working and studying during TMS; our guide to working, studying and driving during a course has details. For everything else, start at the TMS guide or read about TMS treatment for depression.
Sources
- Safety and recommendations for TMS use in healthy subjects and patient populations, with updates on training, ethical and regulatory issues: Expert Guidelines. Clinical Neurophysiology, 2021. europepmc.org
- Transcranial magnetic stimulation in the treatment of major depressive disorder: a comprehensive summary of safety experience from acute exposure, extended exposure, and during reintroduction treatment. Journal of Clinical Psychiatry, 2008. europepmc.org
- Brief Summary of the Neurological Devices Panel Meeting – March 21, 2019: neuroAD Therapy System. U.S. FDA, 2019. fda.gov
- K220177 510(k) Summary – Magnus Neuromodulation System with SAINT Technology. U.S. FDA, 2022. accessdata.fda.gov
- Stanford Accelerated Intelligent Neuromodulation Therapy for Treatment-Resistant Depression. American Journal of Psychiatry, 2020. pubmed.ncbi.nlm.nih.gov
- Canadian Network for Mood and Anxiety Treatments (CANMAT) 2023 Update on Clinical Guidelines for Management of Major Depressive Disorder in Adults. Canadian Journal of Psychiatry, 2024. pmc.ncbi.nlm.nih.gov
- The cognitive effects of electroconvulsive therapy in community settings. Neuropsychopharmacology, 2007. pubmed.ncbi.nlm.nih.gov
- Objective cognitive performance associated with electroconvulsive therapy for depression: a systematic review and meta-analysis. Biological Psychiatry, 2010. pubmed.ncbi.nlm.nih.gov
- Repetitive transcranial magnetic stimulation versus electroconvulsive therapy for major depression: a systematic review and meta-analysis. Progress in Neuro-Psychopharmacology & Biological Psychiatry, 2014. pubmed.ncbi.nlm.nih.gov
- Efficacy and acceptability of high frequency repetitive transcranial magnetic stimulation (rTMS) versus electroconvulsive therapy (ECT) for major depression: a systematic review and meta-analysis of randomized trials. Depression and Anxiety, 2013. pubmed.ncbi.nlm.nih.gov
- Safety Information. NeuroStar (Neuronetics), 2026. neurostar.com
- Postmarketing Safety of Transcranial Magnetic Stimulation: A 10-Year MAUDE Database Analysis of Adverse Events and Technological Advancements. Journal of Clinical Psychiatry, 2026. pubmed.ncbi.nlm.nih.gov
- Class II Special Controls Guidance Document: Repetitive Transcranial Magnetic Stimulation (rTMS) Systems. U.S. FDA, 2011. fda.gov
- Transcranial Magnetic Stimulation (LCD L33398). CMS Medicare Coverage Database, 2026. cms.gov
- Ketamine versus ECT for Nonpsychotic Treatment-Resistant Major Depression. New England Journal of Medicine, 2023. pubmed.ncbi.nlm.nih.gov
- Cognitive impairment in depression: a systematic review and meta-analysis. Psychological Medicine, 2014. pubmed.ncbi.nlm.nih.gov
- Effects of repetitive transcranial magnetic stimulation (rTMS) on cognitive impairment in depression: A systematic review and meta-analysis. Journal of Affective Disorders, 2025. pubmed.ncbi.nlm.nih.gov
- The effects of non-invasive brain stimulation on cognitive impairment in depression: A systematic review and meta-analysis. Asian Journal of Psychiatry, 2025. pubmed.ncbi.nlm.nih.gov
- SPRAVATO (esketamine) nasal spray, CIII – Prescribing Information (dosage, contraindications, warnings and adverse reactions sections). Janssen / DailyMed (U.S. National Library of Medicine), 2026. dailymed.nlm.nih.gov
FAQs
Does TMS cause memory loss like ECT?
No. Memory loss is not a recognized side effect of TMS, and pooled trials found no reliable cognitive side effects. ECT works differently, through a brief seizure under anesthesia, and can affect memory.
Why do I feel foggy after a TMS session?
Headache, scalp discomfort, fatigue and the depression itself can all make concentration harder, especially in the first week. If the fog is new, severe or not improving, tell your TMS team.
Can TMS be used to treat memory problems?
Not as an established treatment. TMS for Alzheimer's disease and memory decline is still a research question; an FDA advisory panel did not support the one device reviewed for it. The drlewis.com guide to TMS for Alzheimer's disease and memory decline explains the research.
Is it safe to have TMS after ECT?
Having had ECT does not by itself rule out TMS; Medicare's New York policy even lists current ECT among the routes to TMS coverage. Tell your TMS team about your ECT history and any lasting memory effects so they can note a baseline.
Will TMS affect my ability to study or work?
Most people continue working or studying. Plan for possible tiredness or headache early in the course, and avoid sleep loss.
