Study Finds American Indian Adults Exposed to Early Life Trauma More Likely to Develop PTSD and Poor Physical Health in Adulthood


Dec. 9, 2016 – American Indian adults who were exposed to an early life trauma are more likely to develop post-traumatic stress disorder (PTSD) and poor physical health in adulthood according to a study recently published in the American Journal of Human Biology. The study was conducted by researchers at: Dartmouth College; Washington State University, Spokane; and the University of Colorado Anschutz. (A pdf of the study is available upon request).

The study is the first of its kind to examine the relationship between early life trauma, PTSD and adult physical health in American Indians, illustrating the integral role that early life and environmental experiences have on one’s health. The findings are especially important given that some groups of American Indians and Alaska Natives have a prevalence of PTSD that is twice as high ( as the general population.

“It is important for people to understand that exposure to traumatic early life experiences, often as a result of structural inequalities in society, can have substantial impacts on both mental and physical health in later life. Differences in early life trauma exposure could therefore contribute to many of the health inequities we observe among American Indians and other minority groups,” says lead author Zaneta M. Thayer (, assistant professor of anthropology at Dartmouth College.

The study drew on a sample from an earlier mental health study of American Indians from the Northern Plains and Southwest called the American Indian Service Utilization Psychiatric Epidemiology, Risk and Protective Factors Project (AI-SUPERPFP). For the present study, approximately 200 participants were evaluated on their exposure to early life trauma before age 13, including: direct trauma exposure, exposure to traumatic news and witnessing violence. They were diagnosed on if they had PTSD or not, and their physical health was evaluated based on biomarker measurements obtained through a physical examination, blood pressure readings, and bloodwork measuring their fatty acids and cholesterol levels. Using these measurements, the researchers calculated an allostatic load score for each participant, which is a measure of cumulative wear and tear on the body in response to trauma and stress.

Participants were mainly middle aged women, who were an average age of 44 years old during the study. Forty-eight percent of the sample experienced at least one trauma exposure in childhood, and were also found to be significantly more likely to experience substance abuse, trauma exposure in adulthood and to have PTSD. 

Although no direction correlation was found between early life trauma and allostatic load, based on the study’s statistical models, the researchers found that exposure to chronic stress during childhood, when paired with later PTSD development, was associated with poorer physical health, as indexed by increased allostatic load. Remarkably, the relationship between early life trauma, PTSD and elevated allostatic load remained even after adjusting for substance abuse and trauma exposure in adulthood, as well as for other potential factors such as age, education and marital status.

The study sheds further light on the mental and physical health challenges that many American Indians encounter through adulthood and highlights the importance for early interventions during childhood, to help minimize if not prevent, the risk of PTSD development and subsequent poor health later in life. “Our study also underscores the importance of programs, such as those in place by Administration for Children and Families, and Head Start, which help address the needs of children and families in tribal communities” added Thayer.

Zaneta M. Thayer is available for comment at Celestina Barbosa-Leiker, Michael McDonell, Lonnie Nelson, and Dedra Buchwald of Washington State University, Spokane; and Spero Manson of the University of Colorado Anschutz, also served as co-authors of the study.