During a TMS course, the three habits that matter most are simple: sleep a normal amount, keep alcohol low and steady (and never binge or go through withdrawal), and keep your caffeine about the same from day to day. Sleep loss and alcohol withdrawal are both recognized factors that lower the seizure threshold, which is the main reason TMS teams ask about them.
None of this means a late night or a glass of wine will make TMS dangerous. Expert guidelines describe the seizure risk with TMS as very low. The point is to avoid stacking avoidable risk factors on top of that small risk, and to tell the TMS team honestly when something changed.
Why the TMS team asks about sleep, alcohol and caffeine
The most serious acute risk of TMS is a seizure, and expert guidelines describe that risk as very low. In a survey covering 2012 to 2016, seizures happened at fewer than 1 per 60,000 sessions when TMS was given within published guidelines to people without known risk factors. The same survey found risk rose with patient risk factors and that seizures were most likely within the first few exposures to TMS.
The 2021 international safety guideline from the International Federation of Clinical Neurophysiology (IFCN) names everyday factors that can lower the seizure threshold, including sleep deprivation, stress, increased alcohol use and alcohol withdrawal. It also recommends that clinics document these factors, along with medications and infections, while you are in treatment. In its discussion of psychiatric patients, the same guideline lists substance use "(e.g. alcohol, caffeine)" and unstable patterns such as sleep deprivation among predisposing factors.
That is why the daily check-in question, "Anything different since yesterday?", is not small talk. It is part of the safety process. For the wider picture on risk, see TMS side effects, common and rare.
The quick reference
| Habit | What the evidence supports | Practical approach during a course |
|---|---|---|
| Sleep | Sleep deprivation is a named seizure-threshold factor | Protect a normal night before every session, especially in week one; tell the technician after a bad night |
| Alcohol | Increased use and withdrawal are both named factors | No binges; do not stop heavy drinking abruptly without a medical plan; disclose your real intake |
| Caffeine | Listed as a predisposing substance; its effect on TMS outcome is unproven | Keep your usual amount steady; do not add an extra energy drink before a session |
| Recreational stimulants | Cocaine and MDMA are named seizure-threshold factors | Avoid, and tell your team about any use |
Sleep: the factor most within your control
Of the three, sleep matters most. The IFCN guideline notes that studies combining TMS with EEG have found higher cortical excitability after sleep deprivation, even in healthy volunteers. It also cites at least one study, in people with epilepsy, in which the degree of sleep deprivation significantly increased seizure risk.
Depression itself often disrupts sleep, so "just sleep more" is not always possible. A reasonable target, from the American Academy of Sleep Medicine consensus, is that adults sleep 7 or more hours per night on a regular basis. During a TMS course, aim for consistency rather than perfection:
- Keep the same wake time on treatment days and weekends, so Monday's session does not follow a lost Sunday night.
- Avoid pulling an all-nighter for work or school during the course, especially in the first week.
- If insomnia is part of your depression, tell your psychiatrist. Behavioral treatment for insomnia exists, and there is more on it in why CBT-I is the standard insomnia treatment.
- If you slept very little before a session, say so at check-in. Your team can decide whether to go ahead; you do not have to judge that yourself.
Do not change sleep medications on your own to "get better sleep for TMS." Medication changes during a course belong in a conversation with your prescriber; see keeping or changing medications during TMS.
Alcohol: steady and low beats sudden changes
Alcohol shows up twice on the IFCN list: increased drinking, and alcohol withdrawal. The second is easy to overlook. Someone who drinks heavily every day and decides to stop cold on the day TMS starts may be creating more risk, not less.
A real case illustrates the point. In the pivotal deep TMS depression trial, the one generalized seizure happened during a participant's ninth session, and the investigators attributed it to heavy drinking the night before, which she had not disclosed, and possible alcohol withdrawal. She had no lasting effects.
Practical guidance during a course:
- No binge drinking, particularly the night before a session.
- Be honest about your usual intake at the consultation. The TMS team is not judging; they need an accurate baseline.
- If you drink daily and want to cut down, plan it with your doctor. Stopping suddenly after heavy use can cause withdrawal, which needs medical supervision on its own terms.
- Remember the mood effect. Alcohol use disorder and major depression are closely linked, and the evidence suggests heavier alcohol involvement raises the risk of depression. Cutting back can help the depression you are treating.
If drinking feels hard to control, that is worth treating directly, not just working around. The practice's article on medications used for alcohol use problems is a starting point for that conversation.
Caffeine: consistency over cutting out
Caffeine has the least evidence of the three, so the advice is modest. The IFCN guideline lists caffeine alongside alcohol as a substance that can predispose psychiatric patients to seizures, without giving a dose. FDA describes 400 milligrams a day, about two to three 12-ounce cups of coffee, as an amount not generally associated with negative effects for most adults. It notes that toxic effects such as seizures can occur with rapid intake of around 1,200 milligrams.
Whether caffeine changes how well TMS works is an open question. In one small post hoc analysis of 20 healthy volunteers, drawn from studies that paired 10 Hz stimulation with the drug d-cycloserine, people who did not use caffeine showed greater motor-cortex plasticity after 10 Hz stimulation than daily caffeine users, and the authors called for well-powered prospective studies. That is a hypothesis, not a reason to quit coffee before TMS.
A sensible middle path:
- Keep your normal daily amount steady through the course. FDA notes that caffeine withdrawal is not considered dangerous but can be unpleasant, and a sudden change makes it harder to tell what is causing a new symptom during the course.
- Skip the extra energy drink or pre-workout supplement before a session. High-dose stimulant products are the realistic concern.
- Watch the timing. In a home-sleep study, 400 mg of caffeine taken even 6 hours before bed significantly disrupted sleep. Late-afternoon coffee can quietly undo the sleep advice above.
The day of a session
- Sleep your usual amount the night before.
- Have your normal caffeine, at your normal time, not more.
- Eat something and drink water. If you ever feel faint, a team handles it by lowering your head, rehydrating and cooling the skin.
- No alcohol before treatment, and none to excess the night before.
- At check-in, mention a bad night, a heavy evening, a new medication, a fever or an infection.
For what the sessions themselves feel like, read what TMS feels like in your first week. For the bigger picture of exercise, food and sleep across the whole course, see supporting a TMS course with sleep, movement and nutrition, and for the practical lead-up, the TMS preparation checklist.
When to call your team instead of waiting
- You had a drinking episode and feel shaky, sweaty or anxious the next day (possible withdrawal).
- You have gone several nights with very little sleep.
- You started or stopped a medication, including over-the-counter sleep or stimulant products.
- You have a fever or infection, both named by the IFCN guideline as factors to document.
The TMS team can shift a session, adjust timing or simply note it. Telling them is always the right move. You can find more practical guides in the TMS guide for patients, and an overview of the treatment on the TMS therapy page. For the clinical detail on seizure figures, the physician's guide covers TMS safety and seizure risk in depth.
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
- Seizures from transcranial magnetic stimulation 2012-2016: Results of a survey of active laboratories and clinics. Clinical Neurophysiology, 2019. europepmc.org
- Efficacy and safety of deep transcranial magnetic stimulation for major depression: a prospective multicenter randomized controlled trial. World Psychiatry, 2015. pmc.ncbi.nlm.nih.gov
- Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Journal of Clinical Sleep Medicine, 2015. pmc.ncbi.nlm.nih.gov
- Spilling the Beans: How Much Caffeine is Too Much?. U.S. Food and Drug Administration, 2024. fda.gov
- Chronic caffeine consumption curbs rTMS-induced plasticity. Frontiers in Psychiatry, 2023. pubmed.ncbi.nlm.nih.gov
- Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine, 2013. pubmed.ncbi.nlm.nih.gov
- Alcohol and depression. Addiction, 2011. pubmed.ncbi.nlm.nih.gov
FAQs
Can I drink alcohol at all during a TMS course?
Many people have an occasional drink during a course. The concerns are heavy drinking, binges and withdrawal after heavy use, which expert guidelines name as factors that can lower the seizure threshold. Ask the TMS team what is reasonable for you and be honest about your usual intake.
Should I stop drinking coffee before TMS?
There is no evidence that you need to. Keeping your usual amount steady is the cautious approach. Avoid adding high-dose energy drinks or stimulant supplements before sessions, and keep caffeine away from the evening so it does not cost you sleep.
I barely slept last night. Should I skip my session?
Do not decide alone. Tell the technician at check-in. Sleep deprivation is a recognized seizure-threshold factor, and your team can decide whether to go ahead, delay or simply note it.
Does cannabis matter during TMS?
The IFCN safety guideline mentions marijuana use, both therapeutic and recreational, among factors that may lower the seizure threshold but have not been specifically studied. Tell the TMS team if you use it.
Will cutting back on alcohol make TMS work better?
No study shows that directly. Heavier alcohol use is linked to a higher risk of depression, though, so cutting back may help your mood independently of TMS.
