Over the last few years, you have probably seen the phrasing "Trigger Warning", or "TW" in posts online, or heard someone say that they were "triggered" by something. Triggers are defined as anything that might cause a person to recall/relive a traumatic experience they went through in their past. For example, graphic images resulting from a fight scene in a movie (think James Bond style - explosions, bullets, blood) can be triggering for people with violent trauma in their past. Less obvious things, which can be anything from a song, to a smell, or even particular colors, can also be triggers depending on someone's experience.
A trigger warning is simply a way to let people know that the content within might contain triggers. This gives those people who WOULD be triggered by such content the opportunity to avoid it all together. Triggers aren't anything new in relation to mental health, but attention has been brought to them much more in casual conversation and in mainstream media in recent years, which has lead to confusion and debate regarding the topic.
Triggers are very real
With regard to mental health, a trigger refers to something that effects your emotional state. Usually, this effect is serious/severe and can cause extreme overwhelm or distress. A trigger can affect your ability to be present in the moment, and can bring up specific thoughts or emotional patterns that influence your behavior.
Trigger reasons, and the triggers themselves, vary widely and can be both internal and external. Phrases, sounds, and odors can all be triggers to people who have experienced the traumatic events such as:
military conflict
emotional abuse
physical assault
rape
loss of a loved one
Reading, watching, or absorbing content about something similar to a person's traumatic event can trigger distressing flashbacks or memories for people who are living with Post Traumatic Stress Disorder (PTSD).