Brain zaps are brief sensations that feel like a small electric shock in your head. Some people feel them in their arms or legs too. They are most often reported when an antidepressant is reduced, stopped or missed, especially SSRIs and SNRIs. The NHS, NICE and the Royal College of Psychiatrists all list them as a withdrawal symptom.
They can be alarming, but they are a recognised effect. For many people they fade as the body adjusts. For some they last much longer. The thing that helps most is a planned, gradual reduction agreed with whoever prescribed the medicine. Do not stop or cut down on your own.
Call 112 or 999 in Ireland, 999 in the UK, or 911 in the US, or go to an emergency department, if:
Speak to your prescriber straight away if:
Free support, any time:
People describe them as a brief jolt or shock inside the head. The Royal College of Psychiatrists (RCPsych) describes "the feeling of an electric shock in your arms, legs, or head". It adds that turning your head to the side can make them worse. The NHS describes feeling "like you've had an electric shock in your head".
Medical documents use more formal terms. NICE lists "altered sensations (for example, electric shock sensations)" among withdrawal symptoms. The US label for sertraline lists "sensory disturbances (e.g., paresthesia, such as electric shock sensations)".
Zaps often come with other withdrawal symptoms. NICE lists dizziness, irritability, anxiety, sleep problems, sweating, nausea, palpitations and headaches. The RCPsych adds vivid dreams, a feeling that things are not real, and inner restlessness.
This is where brain zaps are best described. NICE says withdrawal symptoms can happen with all the main classes of antidepressant. That includes SSRIs such as sertraline, SNRIs such as venlafaxine, tricyclics and MAOIs. NICE singles out paroxetine and venlafaxine as more likely to cause them.
The RCPsych puts duloxetine, mirtazapine, paroxetine and venlafaxine in its highest-risk group for withdrawal. That grouping is about withdrawal in general, not zaps specifically.
You do not have to be stopping for good. NICE warns that missing doses, or not taking a full dose, can cause withdrawal symptoms. The RCPsych notes that symptoms can start within a day or two for some antidepressants, even after a single missed dose.
Fluoxetine leaves the body much more slowly than most antidepressants. The RCPsych says symptoms after stopping it can start days or even weeks later. That delay can make the link easy to miss.
Almost all of the published research on brain zaps concerns antidepressants. If you have zap-like sensations and have not changed any medicine, tell your GP. Do not assume the cause yourself.
Nobody has a reliable figure for brain zaps on their own. The research counts withdrawal symptoms as a group, and estimates vary widely.
The RCPsych says between a third and a half of people who take an antidepressant get some withdrawal symptoms. A 2024 meta-analysis in The Lancet Psychiatry pooled 79 studies and 21,002 patients. It then allowed for symptoms people also report when stopping a placebo. On that basis, about 1 in 6 to 7 people get withdrawal symptoms caused by the drug. A 2025 reanalysis by other researchers, using only five studies with purpose-built withdrawal measures, found 55%. Its estimate was very uncertain (31% to 81%) and did not subtract placebo effects. We set out that disagreement in our SSRI explainer.
The most detailed studies of zaps themselves come from online surveys and forum posts. In 2018, researchers analysed 595 posts on a lay mental health website. Venlafaxine and paroxetine came up more often than their prescribing rates would suggest, and fluoxetine less often. A 2022 follow-up questionnaire drew 3,141 responses. These were self-selected samples, so they describe experiences well but cannot tell us how common zaps are.
The RCPsych says the cause of antidepressant withdrawal symptoms "is still poorly understood". Its working explanation is that the brain and body slowly adjust to the medicine. If it is removed too quickly, they need time to adjust back.
On zaps specifically, the evidence is thin. The 2022 survey authors called brain zaps "a barely examined and poorly understood symptom". Their data hinted at two things worth studying:
A 2026 narrative review proposed that long-term use reshapes serotonin and glutamate signalling. It suggested that stopping may cause a temporary "overcorrection" in sensory networks. That is a hypothesis, not a tested explanation.
NICE guidance (NG222, published June 2022) says:
The RCPsych goes further. It says everyone should taper, and that even after a few weeks' use it is best done over at least four weeks. After many months or years, it advises reducing over months or longer. Some people need to reach a very low dose, as low as 2% of the original, before stopping. Its guide was written with experts including Dr Mark Horowitz and Professor David Taylor.
Medicines labels agree on the principle. The UK sertraline prescribing information advises gradual tapering. The US label recommends gradual reduction "whenever possible".
The research behind tapering is weaker than the guidance might suggest. A 2025 meta-analysis found withdrawal symptoms in 34.5% of people who tapered and 42.5% of those who stopped abruptly. That difference was not statistically significant. A 2021 Cochrane review found most tapers studied lasted four weeks or less, and rated the evidence very low certainty. So the trials mostly tested quick tapers, not the slower ones now recommended.
That gap is a reason for care, not for stopping abruptly. Guidance from NICE and the RCPsych still advises against stopping suddenly.
Everything here is to be done with your prescriber, not instead of them.
There is no treatment proven to stop brain zaps. Be wary of anyone selling one.
This matters, because the answers lead in different directions. The RCPsych gives three clues:
Fluoxetine blurs the timing clue, because its symptoms can start late. Panicky feelings can be withdrawal too, which our panic attack explainer may help you describe.
NICE and the RCPsych are UK bodies. The US sertraline label makes the same core point about gradual reduction. Wherever you live, the first step is the same: speak to your GP or prescriber.
Tapering options depend on which tablet strengths and liquids are available where you live. The RCPsych notes this for the UK, so ask your pharmacist what is available locally. You can report side effects to the HPRA in Ireland or the Yellow Card scheme in the UK.
For wider context, see our guides to what works for depression and what works for anxiety.
They are frightening, but they are listed among expected withdrawal symptoms. NICE describes withdrawal symptoms as common and usually time-limited. Tell your prescriber about them. Get emergency help if you have stroke signs or thoughts of harming yourself.
NICE says withdrawal symptoms usually go within one to two weeks. Sometimes they last several weeks, and occasionally several months. The RCPsych says some people have symptoms for months or more than a year.
Yes, if you miss doses or take less than your usual dose. NICE lists both as causes of withdrawal symptoms. If this keeps happening, tell your prescriber.
Only with your prescriber's advice. For severe symptoms, NICE says prescribers should consider restarting the previous dose, then tapering more slowly. Symptoms may take a few days to settle after restarting.
No. The RCPsych explains that addiction involves cravings, loss of control and a "high". Antidepressants can cause physical dependence, meaning the body has adapted to the medicine. That is what produces withdrawal symptoms.
This article is general information, not medical advice. Never stop, reduce or change a prescribed medicine without talking to your prescriber. If you are in crisis, use the numbers in the box above.
Reviewed by: Proco Team
Last updated: November 2026