The CDC-Kaiser Permanente adverse childhood experiences study is one of the largest investigations of childhood abuse and neglect and household challenges and later-life health and well-being.

Adverse childhood experiences, or ACEs, are potentially traumatic events that occur in childhood (0-17 years). For example:

• experiencing violence, abuse, or neglect

• witnessing violence in the home or community

• having a family member attempt or die by suicide

Also included are aspects of the child's environment that can undermine their sense of safety, stability, and bonding, such as growing up in a household with:

• substance use problems

• mental health problems

• instability due to parental separation or household members being in jail or prison.

The more ACEs a child experiences, the more likely he or she is to suffer from things like heart disease and diabetes, poor academic achievement, and substance abuse later in life.

Experiencing many ACEs, as well as things like racism and community violence, without supportive adults, can cause what's known as toxic stress. This excessive activation of the stress-response system can lead to long-lasting wear-and-tear on the body and brain.

• Harvard University Center on the Developing Child: Take the ACE Quiz - And Learn What It Does and Doesn't Mean

• CDC: ACEs Fast Facts

• CDC: Risk and Protective Factors

• CDC: ACEs Prevention Strategies

• CDC: Help Youth At Risk for ACEs

• Child Trends: ACEs are different than child trauma, and it's critical to understand why

• Video: CDC- We Can Prevent ACEs

• Video: TED | How childhood trauma affects health across a lifetime | Dr. Nadine Burke Harris

• Video: ACEs - Impact on brain, body, and behaviour