Tian Dayton's contribution to the understanding of Adult Children of Alcoholics (ACoA) involved expanding the concept beyond the direct effects of alcoholism to encompass broader dysfunctional family dynamics and their psychological impact. In her work, "The ACoA Trauma Syndrome," Dayton posits that the emotional pain originating from a difficult childhood can manifest as a post-traumatic stress reaction in adulthood. She explains that intimate relationships, such as those in partnering and parenting, can reawaken dormant childhood wounds, akin to how external stimuli can trigger memories in trauma survivors. This perspective highlights how unresolved childhood issues can resurface and significantly influence adult emotional and relational experiences.

Dayton's work aligns with the broader goals of the Adult Children of Alcoholics (ACA) fellowship, which seeks to help individuals recover from the effects of growing up in alcoholic or dysfunctional homes. While ACA itself is a fellowship with its own established program and literature, Dayton's theoretical framework offers a specific lens through which to understand the nature of the trauma experienced by adult children. Her emphasis on the "ACoA Trauma Syndrome" provides a framework for recognizing and addressing the deep-seated psychological patterns that can emerge from such formative experiences, framing them as responses to trauma that require healing.

Tian Dayton significantly broadened the scope of what it means to be an Adult Child of Alcoholics (ACoA) by introducing the concept of the "ACoA Trauma Syndrome." In her book on the subject, she detailed how the psychological wounds sustained in childhood, particularly within dysfunctional or alcoholic families, can lead to post-traumatic stress responses in adulthood. Dayton theorized that the very intimacy and vulnerability inherent in adult relationships, such as marriage or parenthood, can act as triggers, reawakening unresolved childhood pain. This is comparable to how a soldier might react to a sudden loud noise, recalling past combat experiences. The core idea is that deep-seated childhood pain, even if dormant for years, can be reactivated by the dynamics of close adult relationships, manifesting as a form of trauma.

While the term "adult children" was popularized by Janet G. Woititz in relation to parental alcoholism, Tian Dayton extended its application. She proposed that the term ACoA could also encompass individuals experiencing post-traumatic stress reactions stemming from their childhood environments, irrespective of whether alcoholism was the sole or primary issue. Dayton's work suggests that the dysfunction and emotional neglect experienced in childhood create a foundation for trauma that continues to affect individuals into their adult lives. This expanded definition acknowledges the multifaceted nature of childhood adversity and its lasting psychological impact, framing these experiences through the lens of trauma recovery.

“"Just as a car backfiring triggers a soldier into unconscious memories of gunfire, when the ACoA grows up and enters the intimate relationships of partnering and parenting, the very vulnerability, dependency and closeness of those relationships can trigger unhealed and unconscious pain from childhood."”