This guide explains TMS treatment, its typical course, common mild effects such as scalp discomfort and headaches, and the need for screening and clinic communication.
TMS Side Effects and Safety: A Washington Patient Guide
Transcranial magnetic stimulation (TMS) is a non-invasive treatment that uses magnetic pulses to stimulate areas of the brain involved in mood regulation. It is usually provided while you are awake in an outpatient clinic, without a general anaesthetic.
TMS was first cleared by the US Food and Drug Administration for major depressive disorder in 2008. It was also cleared for depression with comorbid anxiety in 2021. Like any medical treatment, it has possible side effects and risks. A proper assessment should consider your health history, medicines, previous treatments and any implants or metal in or around your head.
For many people, TMS side effects are mild and manageable. It is still important to know what to expect, what should be discussed before treatment begins, and when to contact the clinic.
What a course of TMS usually involves
A standard TMS course often involves around 36 weekday appointments over six to nine weeks. The exact schedule and type of TMS may vary according to the treatment plan and the clinic.
During a session, a treatment coil is positioned against the scalp. You may hear clicking sounds and feel tapping, knocking or tingling where the coil is placed. The team should explain what the treatment feels like, provide appropriate hearing protection, and check your comfort throughout the session.
The first appointment may include measurements to identify the treatment location and determine settings suitable for you. It is reasonable to ask how the clinic monitors side effects and what happens if you find treatment uncomfortable.
Common side effects: scalp discomfort and headache
The most common TMS side effects are temporary scalp discomfort and headache.
Scalp discomfort can feel like pressure, tapping, tingling or soreness at the treatment site. Some people find the sensation unpleasant at first, particularly during early sessions. The discomfort often becomes easier to tolerate as treatment continues, although experiences vary.
Headaches may occur after a session or during the early stages of a course. They are generally described as mild to moderate and may settle with time. Tell the treating team about any headache, especially if it is persistent, severe, new for you, or accompanied by other symptoms.
If scalp discomfort or headache is affecting your ability to continue, do not simply put up with it. The clinician may be able to review coil positioning, treatment settings, timing or other practical measures. Do not change prescribed medicines or start taking new pain relief without checking with the clinician responsible for your care or another appropriate healthcare professional.
Other effects you may notice during treatment
Some people feel tired after an appointment, while others return to their usual activities straight away. Treatment can also bring up emotional reactions, particularly when someone is living with depression or anxiety. Your mood, sleep, energy and anxiety symptoms should be monitored during the course.
TMS is not designed to cause loss of consciousness, confusion or memory loss. If you experience symptoms that feel unusual or concerning, tell the clinic promptly rather than assuming they are part of treatment.
It can help to keep a simple note of symptoms between sessions. Include when they started, how long they lasted, what they felt like, and whether anything made them better or worse. This gives the treatment team useful information when deciding whether any adjustment is needed.
The rare risk of seizure
Seizure is a rare but serious risk of TMS. Clinics should screen for factors that could increase seizure risk before treatment starts and should have procedures for responding to an emergency.
A history of seizures does not automatically mean that TMS is unsuitable, but it needs careful clinical discussion. The same applies to conditions or circumstances that may affect seizure risk. Your clinician may need to consider your medical history, current medicines, alcohol or drug use, sleep pattern, and any recent changes in your health.
Contact the clinic before your next session if you have been unwell, have had very little sleep, have made a significant change to your medicines, or have experienced symptoms that could be relevant to seizure risk. If a seizure occurs or you believe someone may be having one, seek urgent medical help.
Who may need additional assessment
TMS is not appropriate for everyone without further review. In particular, tell the clinician about any metal or electronic device in or near your head. Some implanted devices or metal objects may be affected by the magnetic field, depending on their type and location.
This can include, for example:
- Metal fragments or shrapnel, especially around the head or eyes
- Implanted electronic devices
- Cochlear implants
- Brain stimulators or other implanted neurological devices
- Aneurysm clips, stents or other surgical hardware
- Previous head, brain, eye, ear or facial surgery
Do not assume an implant is safe or unsafe based on its name alone. Bring any available information about the device, surgery or implant manufacturer to your assessment. The treating clinician can decide whether further checks are needed.
Pregnancy, breastfeeding, neurological conditions, significant head injury, or a personal or family history of seizures are also worth discussing. This does not necessarily rule out treatment, but it may affect whether TMS is suitable and how it is delivered.
What to tell your TMS clinician
An accurate, up-to-date health history is one of the most important parts of TMS safety. Tell the clinician about diagnoses, past treatments and anything that has changed since your referral.
Before starting, discuss:
- Any previous seizure, fainting episode or unexplained loss of consciousness
- Epilepsy or another neurological condition
- Head injury, stroke, brain surgery or brain infection
- Metal, implants, pacemakers, hearing devices or surgical hardware
- All prescribed medicines, over-the-counter products and supplements
- Recent medication changes, including dose increases or stopping medicines
- Alcohol, recreational drug or substance use
- Sleep difficulties, severe sleep loss or major changes to your routine
- Pregnancy, plans for pregnancy, or breastfeeding
- New symptoms such as severe headache, weakness, confusion, vision changes or unusual movements
Continue to update the clinic during the course. A medicine change made by another prescriber, a period of poor sleep, or an emergency visit can be relevant even if it seems unrelated to TMS.
Questions to ask before treatment starts
It is appropriate to ask clear questions about safety. You might ask:
- What side effects are most likely with this form of TMS?
- How will you respond if I have scalp pain or headaches?
- What information do you need about my implants, medicines or medical history?
- Who should I contact outside appointment hours if I am concerned?
- What symptoms mean I should seek urgent medical attention?
- How will you communicate with my GP, psychiatrist or other prescriber?
A clinic should give you the opportunity to understand the expected benefits, limitations and risks before you consent to treatment. You can also ask for information in writing if that would be helpful.
Practical safety during a treatment course
Try to attend appointments as planned and let the clinic know as early as possible if you need to miss one. Keep taking medicines as prescribed unless the clinician managing your medication advises otherwise.
Avoid making unplanned changes to medicines, alcohol intake or substance use during treatment. If you are prescribed a new medicine or experience a significant change in your health, contact the TMS clinic before the next session.
Washington has a wide range of TMS providers, with 97 published clinics listed on TMS Therapy Washington. Directory listings include clinics in Camas, Seattle, Vancouver, Battle Ground, Spokane, Bothell, Olympia, Renton, Liberty Lake, Bremerton, Everett and Bellevue. Availability, assessment processes and insurance arrangements can differ between providers, so confirm details directly with a clinic.
Getting help in Washington
Visit the TMS Therapy Washington clinic listings to compare published providers, the insurance guide for information on plans commonly seen in Washington, and the contact page if you need help using the directory.
This is educational information, not medical advice.
This page is informational and is not medical advice.