TMS Side Effects: What's Common, What's Rare, and Who Shouldn't Get It

TMS (transcranial magnetic stimulation) has a reputation as one of the gentler treatments for hard-to-treat depression — no anesthesia, no medication side effects, and you drive yourself home. That reputation is mostly earned. But "well tolerated" isn't the same as "nothing can go wrong," and if you've searched for TMS you've probably seen stories from people who say it made things worse. Here's what the evidence actually shows.

The short version

• Common side effects are mild and usually fade over the first week or two: headache, scalp discomfort at the coil site, and facial or jaw twitching during treatment.
• The serious risk is seizure, and it's very rare — on the order of well under 1 in 1,000 sessions in large surveys, and lower still for people without risk factors.
• People who shouldn't get TMS include those with non-removable metal or electronic implants in or near the head, and many people with epilepsy or certain neurological conditions.
• Not responding — or feeling worse — is real for some people. It's not usually permanent harm, but it's a signal to talk to the prescribing psychiatrist promptly, not to push through silently.

Common side effects

Most side effects happen during or shortly after a session and get milder as your body adjusts:

• Headache. The most frequently reported side effect, typically mild and manageable with over-the-counter pain relievers like acetaminophen or ibuprofen. It usually lessens after the first week or two.
• Scalp discomfort or pain under the coil. Many people describe a tapping or prickling sensation. Your technician can often adjust coil position or temporarily ramp intensity to make it tolerable.
• Facial, eyelid, or jaw twitching while the pulses fire. This stops when the session does. Some people also notice tooth or jaw ache.
• Lightheadedness after a session, usually brief.
• Noise. The coil makes loud clicks. Earplugs are standard — research consent forms list hearing effects as a risk if they're not worn.

Cleveland Clinic describes TMS side effects as mostly "mild and short-lasting" and notes TMS doesn't cause the memory or thinking problems associated with ECT.

Rare but serious risks

Seizure. This is the risk clinics screen hardest for. A 2019 survey of TMS labs and clinics covering roughly 318,000 sessions found about 0.08 seizures per 1,000 sessions with standard figure-8 coils, with somewhat higher estimates for some other coil types based on very few events. A 2020 literature review concluded overall risk is below 1% and comparable to — or lower than — the seizure risk of several common psychiatric medications. Seizures, when they happen, tend to occur early in a course and during the session itself, where staff are trained to respond. Risk goes up with sleep deprivation, alcohol use or withdrawal, recent medication changes, brain injury, and epilepsy — so tell your clinic about all of these.

Mania or hypomania. Like antidepressants, TMS can occasionally trigger a switch into mania, particularly in people with bipolar disorder. Older pooled data put the rate around 1% in active TMS vs. a similar rate with sham, with a higher rate in bipolar depression than unipolar depression. Warning signs include unusually little need for sleep, racing thoughts, and impulsive behavior — report these immediately.

Fainting is occasionally reported, often related to anxiety or the setting rather than the stimulation itself.

Who shouldn't get TMS

TMS uses a strong magnetic field, so the main exclusions are about metal and seizure risk. Cleveland Clinic and Medicare coverage policies list:

• Non-removable metal or electronic devices in or near the head — aneurysm clips or coils, cochlear implants, deep brain stimulators, vagus nerve stimulators, shrapnel or metal fragments, and stents in the head or neck. Medicare's policy uses a rule of thumb of devices within 30 cm of the coil. (Dental fillings and braces are generally fine.)
• Pacemakers and implanted defibrillators — typically excluded or requiring specialist clearance.
• Seizure disorders or a history of seizures, along with conditions that raise seizure risk such as serious head injury, brain tumors, or stroke.
• Active psychosis in the current episode.

Some insurers also exclude people with recent substance misuse or active suicidality from coverage — in the latter case, faster-acting options like ketamine or Spravato or hospital-based care may be more appropriate.

About "TMS ruined my life" stories

If you search for TMS, you'll find people saying it made their depression worse, triggered anxiety, or left them feeling changed. These accounts deserve to be taken seriously rather than dismissed — and also put in context.

What's documented: headaches, scalp pain, rare seizures, rare mania, and — most commonly — non-response. Large real-world data show roughly half of patients respond and about a third reach remission, which means a substantial share of people go through six weeks of daily sessions without meaningful benefit. That's genuinely disappointing, especially after insurance hoops and time off work.

What's less clear: reports of lasting cognitive changes, personality changes, or permanent worsening. Controlled trials and safety reviews haven't found evidence that TMS causes lasting brain damage or cognitive decline. But clinical trials aren't designed to catch every rare or subjective experience, and mood can genuinely worsen during a course — sometimes because the underlying depression is progressing, sometimes because of agitation, insomnia, or anxiety that some people report early in treatment.

What to do if you feel worse:

1. Tell the technician and ask to speak with the supervising psychiatrist — don't wait for the scheduled check-in. Many clinics measure symptoms weekly with standardized scales for exactly this reason.
2. Ask about adjustments. Intensity, coil position, or protocol (for example, switching sides or to a different stimulation pattern) can sometimes be changed.
3. Stopping is always allowed. You can pause or end TMS at any time. There's no withdrawal syndrome from stopping.
4. Get urgent help for suicidal thoughts or signs of mania — call or text 988, or go to an emergency room.

Bottom line

For most people, TMS side effects are a headache and a sore scalp that fade within a couple of weeks. Seizure is rare and screened for; mania is uncommon and worth knowing the signs of. The biggest real-world disappointment is that TMS doesn't work for everyone. Go in with honest expectations, report changes early, and choose a clinic that measures progress and has a psychiatrist who's genuinely reachable. Our guide to what to expect during TMS treatment covers the process, and you can find a TMS provider near you to start asking questions. If you're weighing TMS against other options, see TMS vs. ketamine.