Trauma refers to an emotional or psychological response to an event or experience that is deeply distressing or disturbing. Traumatic events can be life-threatening (though does not have to be) or involve the threat of harm or injury, and they can have a significant impact on a person's mental, emotional, and physical well-being. Events and experiences that are deemed traumatic are subjective; what is traumatic for you may not be traumatic for someone else. An example of this is a race car driver may manage a car crash with ease and confidence and have no effects on functioning or emotional wellbeing, while a car crash for someone else can be a terrifying, traumatizing experience.

Traumatic events may include physical or sexual abuse, natural disasters, serious accidents, combat experiences, the sudden or expected loss of a loved one, or any other experience that is perceived as overwhelming, terrifying, or threatening to our nervous system. It is likely that the less supported, prepared, and safe we feel can increase how traumatizing an experience may be. Trauma can lead to symptoms such as anxiety, depression, flashbacks, nightmares, and other forms of psychological distress. It can also have long-term effects on a person's mental and physical health, relationships, and overall quality of life.