Before starting any mental health treatment, it is reasonable to ask about side effects. TMS therapy is no exception.
Transcranial magnetic stimulation, or TMS, is a noninvasive treatment that uses magnetic pulses to stimulate targeted areas of the brain. It does not require surgery, anesthesia, or medication circulating throughout the body. But “noninvasive” does not mean “no possible side effects.” Patients should understand what they may feel during treatment, what risks should be discussed beforehand, and when to ask a clinician for guidance.
For patients in Portage, Kalamazoo, and nearby communities, learning about TMS side effects can make the treatment conversation clearer and more informed.
Common TMS Side Effects
The most common TMS side effects are usually related to the treatment area on the scalp. The American Psychiatric Association lists common TMS risks such as scalp discomfort during treatment, muscle twitching during treatment, and mild headaches.
The National Institute of Mental Health also notes that rTMS may cause discomfort where the magnet is placed, tingling or contraction of scalp, jaw, or face muscles, mild headache, brief lightheadedness, or dizziness.
Commonly discussed side effects may include:
- Scalp discomfort
- Tapping or pulsing sensation during treatment
- Mild headache
- Facial muscle twitching
- Tingling or tightness in the scalp, jaw, or face
- Brief lightheadedness or dizziness
- Temporary discomfort at the treatment site
These effects can vary from person to person. Some patients may find the sensation easy to tolerate. Others may need time to adjust or may want to discuss comfort concerns with a clinician.
Less Common but Important Risks
TMS is generally considered well tolerated, but some risks are less common and still important to discuss.
The American Psychiatric Association lists uncommon risks including severe headache, syncope or fainting, hearing loss if appropriate hearing protection is not used, and seizure as a very rare risk. A major safety guideline update in Clinical Neurophysiology also emphasizes that seizure is the most serious acute risk associated with TMS, while noting that risk is low when proper screening and safety procedures are followed.
Less common risks to discuss may include:
- Severe or persistent headache
- Fainting
- Hearing discomfort or hearing-related risk if hearing protection is not used appropriately
- New or worsening symptoms
- Rare seizure risk
Patients should be honest about medical history, neurological history, medications, implanted devices, and any prior seizure history before beginning TMS. Screening helps us identify whether TMS is appropriate and whether any safety concerns need closer review.
Why Screening Matters Before TMS
TMS is not appropriate for everyone. Screening is one of the most important parts of the process because it helps identify safety factors before treatment begins.
We may ask about:
- Medical history
- Neurological history
- Seizure history
- Head injuries
- Implanted metal or medical devices
- Current medications
- Prior psychiatric treatment
- Current diagnosis and symptoms
- History of fainting or other relevant medical concerns
The American Psychiatric Association notes that patients are evaluated before TMS to determine whether they are good candidates, and that people with certain metal implants, aneurysm clips or coils, cochlear implants, cardiac defibrillators, or a history of epilepsy may not be candidates.
This does not mean every patient with a medical history is automatically excluded. It means safety factors should be reviewed carefully before treatment is recommended.
What Patients May Feel During a Session
During TMS, patients commonly describe a tapping, knocking, or pulsing sensation on the scalp. Some may notice facial muscle movement or a tingling feeling near the treatment area. The treatment device may also make sound during stimulation, which is why hearing protection may be used.
TMS does not require anesthesia or sedation. The American Psychiatric Association describes TMS as an outpatient procedure and states that patients generally do not need anesthesia or sedation.
Still, the experience can feel unfamiliar at first. Patients who are concerned about discomfort, noise, headache, anxiety, or sensitivity during treatment should bring those concerns up before starting. We can explain what to expect and what should be reported.
When to Ask a Clinician About Side Effects
Patients should ask a clinician about any side effect that feels concerning, persistent, severe, or different from what they were told to expect.
It may be especially important to ask about:
- Headache that is severe or does not improve
- Scalp discomfort that feels difficult to tolerate
- Dizziness, faintness, or fainting
- Hearing discomfort
- New or worsening mood symptoms
- Increased anxiety, irritability, or sleep disruption
- Any unusual neurological symptoms
- Concerns related to medications, seizure history, implanted devices, or medical conditions
Patients should not try to judge every symptom on their own. It is better to ask questions early, especially when something feels unexpected.
How TMS Side Effects Compare With Medication Side Effects
TMS and medication have different side effect profiles.
Psychiatric medications circulate throughout the body and may affect sleep, appetite, digestion, sexual functioning, energy, mood, weight, or other systems, depending on the medication and the patient. TMS is not a systemic medication. Its side effects are more often localized to the treatment area, such as scalp discomfort, headache, or muscle twitching.
That does not mean TMS is risk-free or better for every patient. It means the risks are different. Some patients may prefer to discuss TMS after medication has not worked well enough or has caused side effects. Others may continue medication while receiving TMS, depending on the treatment plan.
The right comparison depends on the individual patient’s diagnosis, medication history, medical history, and treatment goals.
Safety Questions to Ask Before TMS
Before starting TMS, patients may want to ask safety-focused questions such as:
- Am I an appropriate candidate for TMS?
- What side effects are most common?
- What side effects should I report right away?
- Do any of my medications affect TMS safety?
- Does my medical or neurological history matter?
- Are any implants, devices, or metal objects a concern?
- What should I expect during treatment?
- What happens if I feel discomfort during a session?
- How will symptoms and side effects be monitored?
These questions can help patients have a more informed conversation before treatment begins.
TMS Side Effect Education in Portage and Kalamazoo
At our Portage practice, we offer physician-led psychiatric care and TMS in specific clinical contexts, including treatment-resistant depression, OCD, and depression with severe anxiety. For patients considering TMS, side effect education is part of the broader discussion about diagnosis, treatment history, safety, and clinical fit.
TMS may be an option for some patients, but it is not appropriate for everyone. A careful evaluation can help determine whether TMS should be considered and what safety questions need to be addressed before treatment begins.
Patients can learn more about Mauli Verma, MD, review the mental health conditions we treat, contact our office with insurance and billing questions, or use the patient portal if they are already connected with our practice.
Conclusion
TMS is a noninvasive treatment, but it is still a medical treatment. Common side effects may include scalp discomfort, mild headache, tapping or pulsing sensations, muscle twitching, or brief lightheadedness. Less common risks, including seizure, should also be discussed before treatment.
The safest approach is not to assume that TMS is right for everyone, but to ask careful questions. Patients should understand what side effects may occur, what symptoms should be reported, and how their medical history affects candidacy.
For patients in Portage, Kalamazoo, and nearby communities, our practice can help discuss whether TMS may be appropriate within the context of a physician-led psychiatric evaluation.
Frequently Asked Questions About TMS Therapy
What are the most common side effects of TMS?
Common TMS side effects may include scalp discomfort, tapping or pulsing sensations, mild headache, facial muscle twitching, tingling, or brief lightheadedness. Side effects vary by person.
Can TMS cause seizures?
Seizure is considered a rare but serious risk of TMS. This is one reason screening is important before treatment. Patients should discuss seizure history, neurological history, medications, implanted devices, and other safety factors with a qualified clinician.
Does TMS require anesthesia?
TMS generally does not require anesthesia or sedation. It is different from procedures such as ECT, which involve anesthesia. Patients should still ask what to expect during treatment and what sensations may occur.
Can TMS make symptoms worse?
Some patients may experience new or worsening symptoms during mental health treatment, whether related to the treatment, the underlying condition, medication changes, or other factors. Patients should report mood changes, increased anxiety, sleep disruption, irritability, or other concerning symptoms to their clinician.
Who should not receive TMS?
TMS is not appropriate for every patient. Candidacy depends on diagnosis, medical history, neurological history, seizure risk, implanted devices, medications, and other safety factors. A qualified clinician should evaluate whether TMS is appropriate.
Medical Disclaimer
This blog is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always speak with a qualified healthcare professional about your symptoms, health history, risks, and treatment options. If you are in crisis or thinking about harming yourself, call or text 988 in the United States for immediate support.
References
American Psychiatric Association. (2026). What is transcranial magnetic stimulation? https://www.psychiatry.org/patients-families/what-is-tms
Lerner, A. J., Wassermann, E. M., Tamir, D. I., Segev, A., & Roth, Y. (2019). The risks of repetitive transcranial magnetic stimulation in psychiatric patients: A review of the literature. The Journal of Clinical Psychiatry. https://www.psychiatrist.com/jcp/risks-repetitive-transcranial-magnetic-stimulation-psychiatric-patients-review-literature/
National Institute of Mental Health. (2024). Brain stimulation therapies. https://www.nimh.nih.gov/health/topics/brain-stimulation-therapies/brain-stimulation-therapies
Rossi, S., Antal, A., Bestmann, S., Bikson, M., Brewer, C., Brockmöller, J., Carpenter, L. L., Cincotta, M., Chen, R., Daskalakis, J. D., Di Lazzaro, V., Fox, M. D., George, M. S., Gilbert, D., Kimiskidis, V. K., Koch, G., Ilmoniemi, R. J., Lefaucheur, J. P., Leocani, L., … Hallett, M. (2021). Safety and recommendations for TMS use in healthy subjects and patient populations, with updates on training, ethical and regulatory issues: Expert guidelines. Clinical Neurophysiology, 132(1), 269–306. https://doi.org/10.1016/j.clinph.2020.10.003