A close-up of sparklers in a man's hand. The man's face is out of focus.

trigger in psychology is a stimulus such as a smell, sound, or sight that triggers feelings of trauma. People typically use this term when describing posttraumatic stress (PTSD).

What is a Trigger?

A trigger is a reminder of a past trauma. This reminder can cause a person to feel overwhelming sadness, anxiety, or panic. It may also cause someone to have flashbacks. A flashback is a vivid, often negative memory that may appear without warning. It can cause someone to lose track of their surroundings and “relive” a traumatic event.

Triggers can take many forms. They may be a physical location or the anniversary of the traumatic event. A person could also be triggered by internal processes such as stress.

Sometimes triggers are predictable. For instance, a veteran may have flashbacks while watching a violent movie. In other cases, triggers are less intuitive. A person who smelled incense during a sexual assault may have a panic attack when they smell the same incense in a store.

Some people use “trigger” in the context of other mental health concerns, such as substance abuse or anxiety. In these cases, a trigger can be a cue that prompts an increase in symptoms. For example, a person recovering from anorexia may be triggered by photos of very thin celebrities. When the person sees these photos, they may feel the urge to starve themselves again.

How Are Triggers Formed?

The exact brain functioning behind triggers is not fully understood. However, there are several theories about how triggers work.

When a person is in a threatening situation, they may engage in a fight or flight response. The body goes on high alert, prioritizing all its resources to react to the situation. Functions that aren’t necessary for survival, such as digestion, are put on hold.

One of the functions neglected during a fight or flight situation is short-term memory formation. In some cases, a person’s brain may misfile the traumatic event in its memory storage. Rather than being stored as a past event, the situation is labeled as a still-present threat. When a person is reminded of the trauma, their body acts as if the event is happening, returning to fight or flight mode.

In some cases, a sensory trigger can cause an emotional reaction before a person realizes why they are upset.Another theory is that triggers are powerful because they often involve the senses. Sensory information (sights, sounds, and especially smells) plays a large part in memory. The more sensory information is stored, the easier a memory is to recall.

During a traumatic event, the brain often ingrains sensory stimuli into memory. Even when a person encounters the same stimuli in another context, they associate the triggers with the trauma. In some cases, a sensory trigger can cause an emotional reaction before a person realizes why they are upset.

Habit formation also plays a strong role in triggering. People tend to do the same things in the same way. Following the same patterns saves the brain from having to make decisions.

For example, say a person always smokes while they are driving. When a person gets in the car, their brain expects them to follow the same routine and light a cigarette. Thus, driving could trigger the urge to smoke, even if the person wishes to quit smoking. Someone can be triggered even if they don’t make a conscious connection between their behavior and their surroundings.

What Are Trigger Warnings?

A trigger warning is a notice of potential triggers in future discussion or content. The aim is to let people with mental health concerns avoid or prepare themselves for triggers. It is impossible to predict or avoid all triggers, since many are unique to a person’s situation. Warnings are often reserved for common triggers such as images of violence.

Recently, many students have requested trigger warnings in school. There has been much public debate over whether this practice is appropriate for classrooms.

Opponents of trigger warnings often argue these warnings cater to overly sensitive students. Some claim trigger warnings promote censorship. Others believe they infringe upon teachers’ ability to teach course material.

Advocates often argue trigger warnings are necessary for equal access to education. Triggers can cause flashbacks and panic attacks which disrupt learning. According to the American Psychological Association (APA), triggers are often more distressing if they come as a surprise. Advocates say trigger warnings allow students with posttraumatic stress to feel safe in class.

If a student says they have PTSD, personalized trigger warnings are appropriate. There is little research on the effectiveness of classroom trigger warnings. The APA says specific triggers can be hard to predict. Thus, generic warnings on classroom content may be less effective. If a student says they have PTSD, personalized trigger warnings are appropriate.

The Americans with Disabilities Act (ADA) and the Individuals with Disabilities in Education Act (IDEA) forbid discrimination against people with disabilities. These laws include mental health disabilities such as PTSD. Federal law requires educators to make reasonable accommodations to such individuals.

Federal law does not specifically address trigger warnings. Yet the APA suggests trigger warnings may count as accommodations in some cases. Deliberately triggering a person with PTSD could be a form of discrimination.

Getting Help for Triggers

Trigger warnings are useful in some cases. But avoiding one’s triggers will not treat the underlying mental health concerns. If triggers interfere with someone’s daily life, the person may wish to see a therapist.

In therapy, people can process the emotions concerning their pasts. Some may learn relaxation techniques to cope with panic attacks. Others may learn how to avoid unhealthy behaviors. With time and work, a person can face their triggers with much less distress.


  1. ADA know your rights: Returning service members with disabilities. (2010). U.S. Department of Justice. Retrieved from
  2. Does research support classroom trigger warnings? (2017, July 27). APA Journals Article Spotlight. Retrieved from
  3. Taming triggers for better mental health. (2017, March 31). American Psychiatric Association. Retrieved from
  4. What are PTSD triggers? (2017, February 14). Web MD. Retrieved from

Last Updated: 05-2-2018

  • Leave a Comment
  • Abc


    June 8th, 2017 at 10:07 PM

    Does trigger stacking as described in dog behaviour apply to people too?

  • Jenny


    August 2nd, 2017 at 11:41 AM

    Is it possible to be triggered by a smell differently? For instance I smelt something but I didn’t like it, and then on a different I was feeling emotionally down and not myself, like a lot of sad feelings, then I smelt the same smell as before and I started to remember a terrible event (not even sure which one) but it was a bad period.

  • Jenny


    August 2nd, 2017 at 11:46 AM

    Is it possible to be triggered by the same smell differently? For instance I smelt something and I knew I didn’t like it. On a different day, I was feeling emotionally down and not myself, like a lot of sad feelings, then I smelt the same smell as before and I started to remember a terrible event (not even sure which one) but it was a bad period surrounding a particular relationship.

    How is possible to smell the same thing and react differently? Even after you smelt way after the traumatic experience?

  • Joan C.

    Joan C.

    October 17th, 2017 at 1:58 PM

    I need help , my daughter is austic(spectrum) dis-order and I had her in an day center.Which seem to be good in the 1St 3 years.But The staff members have borrowed money from me and wont pay it back also this place lost her clothing and tablet and food came up missing? My daughter was also being bullied by a classmate (another client) 4 black eyes in less than 6 months? I have text mess. From staff asking for monies.where can I file a complaint

  • Valerie F

    Valerie F

    November 24th, 2018 at 12:42 PM

    Try the better business bureau and if no help there… go to your Attorney General. You can file things thru them. Hope you got some help already, tho…was sad to read this..

  • PhilisophicalFalaffleWaffle


    October 23rd, 2017 at 1:34 PM

    Yeah, no. Triggering is a slang word that kids use as a joke.

  • SomeGuyJustdoinstuff


    October 23rd, 2017 at 4:55 PM

    I understand where you come from, this trigger stuff has gotten out of control, but these things are real. When actually diagnosed, these are serious business. Like a war veteran with sounds of popping or booming. Don’t discredit psychology just because a lot of people misuse it.

  • Carol


    October 26th, 2017 at 8:54 AM

    Where do you think the kids got the slang? Because an actual thing was appropriated for the purposes of making fun at others’ expense, aka bullying. This article was probably written because so many people who will thoughtlessly make “triggered!” jokes, don’t actually know where it comes from… and apparently the point went right over some heads.

  • Felicia g

    Felicia g

    November 28th, 2017 at 12:08 PM

    Yes I totally agree. I work with a lot of mental health patients who have had traumatic experiences. When I hear people say that oh they triggered someone, I just start thinking how sick or ignorant these people must be to actually want to trigger someone. There are even articles written on how to trigger a liberal. I drives me crazy they would would do these things so carelessly without caring what triggering actually means. I have seen first hand and it is a horrible thing to watch someone go through it.

  • RMD


    May 5th, 2018 at 10:55 AM

    So you’ve never had dizzy fits and broken down crying because you re-experienced a traumatic event? I’d love to be you.

  • Pan dulce tambien

    Pan dulce tambien

    March 3rd, 2019 at 8:49 PM


  • Person


    March 3rd, 2019 at 8:47 PM

    So I was in the school courtyard and someone tried hitting me and I had a flashback of when I was abused as a younger kid, and at first, I didn’t know what it was all I knew was that I broke down crying this article has really helped me.

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