TMS is a non-invasive depression treatment whose common side effects include temporary scalp discomfort and headaches, while severe or unusual symptoms should be reported promptly.
TMS Side Effects and Safety: An Arizona Patient Guide
Transcranial magnetic stimulation (TMS) is a non-invasive treatment that uses magnetic pulses to stimulate targeted areas of the brain. It is most often considered for major depressive disorder, particularly when other treatments have not provided enough benefit or have caused difficult side effects.
TMS does not involve surgery, anaesthesia or electric current passing through the body. You remain awake and can usually return to ordinary activities after an appointment. A standard course commonly involves weekday sessions over around six to nine weeks, with about 36 appointments in total.
Like any medical treatment, TMS has possible side effects and safety considerations. Understanding them can help you have an informed conversation with a clinician and know what to report during treatment.
The most common TMS side effects
The most commonly reported side effects are scalp discomfort and headache. These are usually mild to moderate, tend to occur during or shortly after sessions, and often ease as treatment continues.
Scalp discomfort
During TMS, a magnetic coil is placed against the scalp. The pulses can cause a tapping sensation and small contractions in facial or scalp muscles. Some people find this uncomfortable at first, particularly around the treatment area.
Discomfort may feel like:
- Tapping, knocking or tingling on the scalp
- Tenderness where the coil has been positioned
- Brief facial muscle twitching during pulses
- Sensitivity around the forehead or temple
The treating team can often make practical adjustments to improve comfort. This may include changing the coil position slightly, reviewing the stimulation setting or allowing short breaks during the session. It is important to mention discomfort rather than trying to tolerate a level of pain that feels unreasonable.
Headache
Headache is also relatively common, especially early in a course of TMS. For many people, it is temporary and manageable with usual measures recommended by their clinician.
Tell the clinic if headaches are severe, persistent, changing in character or accompanied by other symptoms such as confusion, weakness, visual changes or vomiting. Those symptoms need medical assessment rather than being assumed to be a routine TMS effect.
Some people experience fatigue after a session, although many do not. Temporary light-headedness can also occur. If you feel unwell after treatment, ask whether you should rest before driving or returning to work, particularly during your first few sessions.
Serious risks: seizures are rare
The most important rare risk associated with TMS is seizure. A seizure is a sudden episode of abnormal electrical activity in the brain. Modern TMS protocols include safety screening and carefully set treatment parameters to reduce this risk.
Seizures during TMS are considered rare, but the possibility is taken seriously. Clinics should have procedures for responding to a medical emergency, and your treatment team should review factors that may increase seizure risk before treatment begins and during the course.
Factors that may be relevant include:
- A personal history of seizures or epilepsy
- A previous serious head injury
- Certain neurological conditions
- Use of medicines that can lower the seizure threshold
- Recent major changes to medication doses
- Severe sleep deprivation
- Heavy alcohol use, alcohol withdrawal or use of recreational drugs
- Acute illness, including fever in some circumstances
Having one of these factors does not always mean that TMS is impossible. It does mean the clinician needs to assess your situation carefully and decide whether TMS is appropriate, and if so, how it should be delivered safely.
Do not make sudden changes to prescribed medicines, alcohol intake or other substances in an attempt to prepare for TMS. Speak with the clinician overseeing your care first.
Metal implants and implanted medical devices
Because TMS uses a strong magnetic field near the head, certain implanted metal objects or electronic devices may make treatment unsuitable or require specialist assessment.
In particular, tell the clinic about any non-removable metal in or near your head. This can include some clips, plates, coils, fragments or implants following injury or surgery. Dental fillings, braces and most routine dental work are not usually a barrier, but they should still be disclosed.
You should also tell the clinician if you have an implanted medical device, such as a cochlear implant, deep brain stimulation system, implanted nerve stimulator, medication pump, cardiac device or other electronic implant. Whether TMS can be considered depends on the specific device, its location and the manufacturer’s guidance. The clinic may need information from your surgeon, neurologist, cardiologist or device provider.
Do not assume an implant is safe or unsafe based on information online. Bring device details, implant cards or previous medical records if you have them.
Conditions and circumstances to discuss
A thorough TMS assessment should consider your wider health, not only your depression symptoms. Be open about physical and mental health conditions, even if they seem unrelated.
Tell the clinician about:
- Any past seizure, epilepsy diagnosis or unexplained blackout
- Head injury, stroke, brain surgery or neurological illness
- Migraines, especially if severe or associated with neurological symptoms
- Hearing problems or sensitivity to sound
- Pregnancy, plans for pregnancy or breastfeeding
- Bipolar disorder, psychosis or previous episodes of mania or hypomania
- Substance use, including alcohol, cannabis and non-prescribed drugs
- Current sleep problems, particularly prolonged insomnia
- Recent illness, fever or significant dehydration
TMS sessions involve a clicking sound, and clinics normally provide hearing protection. Let the team know if you have tinnitus, hearing loss, ear surgery or other hearing concerns.
For people with bipolar disorder, treatment planning requires particular care. Depression can be part of bipolar illness, but any antidepressant treatment, including TMS, should be considered in the context of possible mood elevation or mania. Contact your clinician promptly if you develop unusually high energy, markedly reduced need for sleep, racing thoughts, impulsive behaviour or agitation.
Medicines: keep the clinic updated
Bring an up-to-date list of all medicines to your assessment and appointments. Include prescriptions, over-the-counter products, vitamins, herbal remedies and supplements.
Medication information matters because some drugs may affect seizure risk, sleep, anxiety or headache. The clinic also needs to know if another prescriber changes your treatment while you are having TMS.
In Arizona, people may receive care through several different health systems or prescribers. Whether you use Blue Cross Blue Shield of Arizona, Banner Health Plans, Aetna, Cigna, UnitedHealthcare, AHCCCS, Medicare, a Medicare Advantage plan or TRICARE West, your TMS clinic may need records or authorisation information. Insurance arrangements are separate from clinical safety, but accurate medication and medical history information remains essential regardless of cover.
What happens if you feel unwell during treatment?
Speak up during a session if you feel pain, panic, dizziness, unusual sensations or anything that worries you. The team can pause treatment and assess what is happening.
Contact the clinic between sessions if you develop:
- A severe or worsening headache
- New neurological symptoms
- A seizure or possible seizure
- A major medication change
- Significant sleep loss
- A new medical diagnosis or procedure
- Pregnancy
- Increased alcohol or substance use
- New symptoms of mania, psychosis or worsening depression
If you have immediate concerns about your safety, including thoughts of harming yourself or others, seek urgent help through emergency services or a local crisis service rather than waiting for the next TMS appointment.
Choosing a clinic and asking safety questions
TMS Therapy Arizona lists 196 published clinics across the state, including listings in Phoenix, Gilbert, Tucson, Yuma, Prescott, Mesa, Scottsdale, Prescott Valley, Peoria, Chandler, Glendale and Green Valley. Availability and treatment approaches can differ between providers.
When contacting a clinic, useful questions include:
- Who will carry out the initial medical assessment?
- How do you screen for seizure risk and implanted devices?
- What happens if I experience significant discomfort?
- What emergency procedures do you have in place?
- How will medication changes be managed during treatment?
- Will you communicate with my GP, psychiatrist or other prescriber if needed?
- What should I do if I feel unwell between appointments?
A safe TMS programme should make room for questions, review changes in your health and take side effects seriously throughout the course.
Getting help in Arizona
Use the TMS Therapy Arizona clinic listings to find providers in your area, review the insurance guide for cover-related information, and visit the contact page if you need help using the directory.
This information is educational only and is not medical advice.
This page is informational and is not medical advice.