For infants and toddlers, the immediate impact can be seen in developmental delays, self - harming behaviors,
inconsistent emotional functioning, inappropriate social interactions, and aggressive behaviors.
Specifically, the ACE Study model relies strongly on the idea that adverse childhood experiences create a burden of psychological stress that changes behavior, cognitions, emotions, and physical
functions in ways that promote subsequent health problems and illness.22 Among the hypothesized pathways, adverse childhood experiences lead to depression and posttraumatic stress disorder, which in turn can lead to substance abuse, sleep disorders, inactivity, immunosuppression, inflammatory responses, and
inconsistent health care use, possibly leading to other medical conditions later in life.23, 24 Therefore, childhood behavioral and
emotional symptoms very likely represent a crucial mediator linking adverse childhood experiences and the longer term health - related problems found in the ACE substudies.