Brain zaps

How it works

A zap is short. The most common reported length is one second³. Most people describe an electrical jolt, shock, shiver, or vibration inside the head³. Some also hear a swoosh, crackle, or rattle. About 10% report a momentary change in consciousness, such as brief confusion or a feeling of the brain blinking³. Moving the eyes sideways is the clearest trigger³.

There is no formal medical name for the feeling. Doctors list it as one symptom of antidepressant discontinuation syndrome, the group of effects that can follow stopping an antidepressant¹. Medicines that leave the body quickly cause it most. In the 2018 study, venlafaxine made up 23% of mentions among the nine most named drugs². Fluoxetine, which stays in the body far longer, appeared in only 3%, even though it is prescribed often².

The cause is not known. One idea is that after the drug stops, the brain is short of chemical messengers such as serotonin for a time¹. Why eye movement sets them off is not known³.

How common it is

Nobody has counted brain zaps in the general population, or in a fair sample of people stopping an antidepressant. A 2024 survey of 1,148 members of online withdrawal support groups did count them. About 3 in 4 who answered said zaps started or got worse during withdrawal⁴. Members of those groups are not typical of everyone who stops⁴. The only firm figure covers the whole syndrome: about 15% to 50% of people who suddenly stop an antidepressant get withdrawal symptoms of some kind, and zaps are one of the listed symptoms¹. Both studies that looked only at zaps recruited people who already had them, 595 forum posts in 2018 and 3,141 questionnaire replies in 2022, so neither can give a share²³. Following everyone who stops a drug would fix that.

Is it a problem?

Usually not. No study has looked at whether zaps harm the brain. In a small number of people they last months or years and cause real disability².

For most people they fade as the body adjusts. In the 2018 study, about a third of the reports that gave a length said the zaps lasted a month or less. About a quarter said 5 to 30 years². Those were people who went online to complain, so the long cases are over-represented.

If you get zaps after changing, lowering, or missing a dose, tell the doctor who prescribed it. Do not stop a medicine on your own. Lowering the dose slowly can make them milder, but it does not always stop them¹². See a doctor if the zaps come with fainting, confusion, or jerking limbs.

History and culture

The name “brain zaps” was coined by patients describing the feeling to each other on internet discussion boards, not by doctors². The medical literature adopted it later.