What is Trauma?

Defining Trauma

Trauma is a pervasive problem. It results from exposure to an incident or series of events that are emotionally disturbing or life-threatening with lasting adverse effects on the individual’s functioning and mental, physical, social, emotional, and/or spiritual well-being.

Experiences that may be traumatic include:

  • Physical, sexual, and emotional abuse
  • Childhood neglect
  • Living with a family member with mental health or substance use disorders
  • Sudden, unexplained separation from a loved one
  • Poverty
  • Racism, discrimination, and oppression
  • Violence in the community, war, or terrorism

Although trauma can occur at any age, it has particularly debilitating long-term effects on children’s developing brains. Often referred to as adverse childhood experiences (ACEs), exposure to these experiences is common across all sectors of society:


U.S. adults with at least one ACE


U.S. adults with three or more ACEs

However, research has shown that the risk for ACEs is particularly elevated within certain populations such as people who identified as black, Hispanic, or multiracial; people with less than a high-school education; people with low-income or who were unemployed or unable to work; and people who identified as gay, lesbian, or bisexual.

Effects of Trauma on Health

The landmark ACE Study and the Philadelphia Urban ACE Study reveal that the more a child is exposed to stressful and potentially traumatic experiences, the greater his or her risk for chronic health conditions and health-risk behaviors. Traumatic events can have deleterious effects on health at any age.

What are the long-term effects of trauma on health?

The original ACE Study asked people to indicate the number of traumatic events they had experienced prior to age 18 and provided them with a corresponding “ACE score.” Compared to people with no ACEs, individuals with an ACE score of four or more were approximately:

2 times

as likely to smoke

2.5 times

more likely to have sexually-transmitted infections

4 times

more likely to have chronic obstructive pulmonary disease

7 times

more likely to consider themselves an alcoholic

10 times

as likely to have injected street drugs

12 times

as likely to have attempted suicide

What is the relationship between trauma and health-risk behaviors?

People affected by trauma may develop coping mechanisms to help alleviate the emotional and/or physical pain they feel as a result of trauma. Sometimes, these strategies involve maladaptive behaviors — such as unhealthy eating, tobacco use, or drug and alcohol use. These coping mechanisms may provide some relief, but they can also simultaneously contribute to anxiety, social isolation, and chronic diseases.

What is the impact of trauma on relationships?

Regardless of the type of trauma a person has experienced, traumatic experiences impact relationships. This includes, but is not limited to, relationships between people, communities, and the delivery systems that support individuals’ health and social needs. When a person experiences trauma, he or she may feel unsafe, betrayed, and/or have difficulty trusting others. This can lead to heightened emotions, such as anger or aggression, or a tendency toward shame, numbing, and/or isolation. Within the context of health care, this can negatively impact the bond between a patient and their provider, and thus a patient’s engagement in care.

Can the effects of trauma be avoided or addressed?

Protective factors, such as supportive relationships with family members, a teacher, or others in the community, can help shield individuals from the effects of trauma and build resilience to help overcome adversity and confront challenges. Trauma-informed approaches to care, including relational healing and trauma-specific treatments, can help patients begin processing their experiences in a healthy way.

The Science of Trauma

Although the field of trauma-informed care is still coalescing, our understanding about how people’s brains and bodies respond to trauma — and the negative long-term effects of toxic stress on health — is well understood. Toxic stress is an emotional and/or physical response that occurs when a person experiences strong, frequent, and/or prolonged adversity without adequate support.

How does trauma affect neurobiology and the physical development of children?

In the first 1,000 days of life, children’s brains are in a critical period of development. Trauma can negatively impact areas in the brain responsible for cognitive functions, such as short-term memory and emotional regulation. This is due in part to the fact that the body regulates stress through the release of two critical hormones: cortisol and adrenaline. Exposure to these stress hormones plays an important role in keeping people safe during times of danger; however, repeated or prolonged exposure is associated with poorer early childhood brain development.

What does experiencing childhood trauma mean for adults?

Adults who experienced trauma in childhood are often “wired” differently than those who did not. Their brains, primed to deal with nearly constant stress, can struggle to respond appropriately to situations that would otherwise appear normal and non-threatening. This partly explains why many adult trauma survivors struggle with depression, anxiety, and other issues related to emotional regulation. These resulting mental health issues can contribute to long-term difficulties maintaining healthy relationships, and lead to problems at school and/or work.

Why do traumatic experiences impact some people more than others?

Many children facing abuse and neglect carry the markers of stress, such as increased cortisol levels, well past the time of exposure. Exactly how stress alters the structure of our brains — and even our DNA — is not yet fully understood. However, research has shown that “protective factors,” such as a loving caregiver, can decrease the impact of traumatic events.