The term “ACEs” originated in a 1998 study by the Centers for Disease Control and Prevention and a Kaiser Permanente study that found significant linkages between adverse childhood experiences (ACEs) and a range of negative health outcomes. ACEs are potentially traumatic experiences, such as neglect, experiencing or witnessing violence, and death or illness in the family. Tools to assess for exposure to ACEs and trauma include a series of questions to identify a person’s experiences before age 18.
The impact of childhood trauma appears to increase with the accumulation of a higher number of ACEs. Current research indicates that individuals with four or more ACEs are two to five times as likely to develop clinical depression, substance use disorders, suicidal ideations and attempts, and numerous chronic health conditions, including diabetes, cancer, and cardiovascular and respiratory diseases compared to those with no ACEs1.
The impact of ACEs is evident across the lifespan. In children, high ACE scores contribute to the risk of anxiety and depression, developmental delays, negative cognitive and socioemotional health issues, academic challenges, behavioral health issues, and specialized health needs1. ACEs also impact education and financial prospects—ACEs decrease the likelihood of high school completion and college degree attainment and increase the likelihood of unemployment, living in poverty, and experiencing homelessness1.
Individual, family, and community factors can impact the likelihood of ACEs. While most ACE assessment tools focus on a child’s household, other adverse experiences, such as bullying, teen dating violence, and community violence, may occur outside the home. Additionally, experiencing some ACEs can increase the risk of experiencing other ACEs2. For example, families with low income are more likely to live in communities with high rates of poverty, food insecurity, and unstable housing, potentially compounding a child’s experiences of traumatic stress.
Children living in poverty, including those experiencing homelessness, are more likely to carry high ACE scores, increasing their risk of developmental challenges and poor health and functioning. The experience of poverty may affect the structures and functions of developing brains, including reduced synapses and cortical size, which affect cognitive processes and behaviors. Poverty has been shown to affect the functions of the prefrontal cortex, impacting language, executive functioning, attention, and memory3.
Trauma also affects an individual’s gene expression, which can impact both the individual and their offspring. Through epigenetics, biochemical processes activate or deactivate specific genes, so the adversities an individual faces, such as the chronic stress of racism, take a toll on the body and accelerate physiological aging4.
Individual and Family Risk Factors
Community Risk Factors
Families with low income
Families with young caregivers or single parents
Families with inconsistent discipline or low levels of parental monitoring
Families with high conflict and negative communication styles
Families with caregivers who were abused or neglected as children
Families that are isolated from other people, such as extended family, friends, or neighbors
Communities with high rates of violence and crime
Communities with high rates of poverty and limited educational and economic opportunities
Communities with unstable housing
Communities where families frequently experience food insecurity
Communities with few community activities for young people
Communities with high levels of social and environmental disorder
Resilience is the ability of an individual to withstand threats to stability in the environment.
Resilience builds over time as an individual develops, and ACEs can alter their capacity for resilience, making it harder to respond to crises in adulthood.
The human brain grows and changes across the lifespan. There are periods of rapid development (particularly during the prenatal, neonatal, early childhood, and adolescence periods) when the brain is especially susceptible to being shaped by adverse experiences. Research indicates that the timing of ACE exposure affects health outcomes; children who only experienced elevated ACE exposure between the years of 0-3 experienced outcomes similar to children with consistently high ACE exposure, regardless of the cumulative difference, and children with decreasing exposure exhibited higher resilience5.
The concept of plasticity also suggests that interventions for adverse experiences can be effective; positive experiences can shape and affect the brain just as adverse ones can. Having supportive relationships and a supportive environment can impact how the body responds to chronic stress. According to the Center on the Developing Child at Harvard University, the most common factor for children who develop resilience is having at least one stable relationship with a supportive parent, caregiver, or other adult6. These relationships provide the personalized responsiveness, structure, and protection that buffer children from developmental disruption. They also build critical capacities—such as planning, monitoring, and regulating behavior—that enable children to adapt to adversity and thrive. This combination of supportive relationships, adaptive skill-building, and positive experiences is the foundation of resilience.
Like risk factors, protective factors can exist within the household and the broader community.
Intersectionality in Risk Factors and Protective Factors
Youth who identify as multiple marginalized identities, such as BIPOC (Black, Indigenous, People of Color) or LGBTQ+, can be more susceptible to negative experiences and chronic stress. Among those who identify as Black and LGBTQ+, high rates of youth report symptoms of generalized anxiety disorder, major depressive disorder, self-harm, and suicidal ideation7. Relatedly, reported risk factors include:
experiences in conversion therapy
homelessness or instability due to sexual orientation or gender identity
discrimination based on sexual orientation or gender identity
threats or experiences of violence based on sexual orientation or gender identity
This research also identified high-impact protective factors for marginalized youth:
Having at least one supportive person in their life
High family support
Access to at least one in-person LGBTQ-affirming space
 Lipina, Sebastian J, and Michael I Posner. 2012. "The impact of poverty on the development of brain networks." National Library of Medicine. doi:10.3389/fnhum.2012.00238.
 Sullivan, Shannon. 2013. "Inheriting Racist Disparities in Health." Critical Philosophy of Race 190-218.
 McKelvey, Lorraine M, Nicola A Connors Edge, Shalese Fitzgerald, Shashank Kraleti, and Leanne Whiteside-Mansell. 2017. "Adverse childhood experiences: Screening and health in children from birth to age 5." Families, Systems, & Health 420-429.