"We saw that things like intractable smoking, things like promiscuity, use of street drugs, heavy alcohol consumption, etc. , these were fairly common in the backgrounds of many of the patients. . . These were merely techniques they were using, these were merely coping mechanisms that had gone into place." Vincent Felitti, MD. When Dr. Vincent Felitti, head of the Department of Preventive Medicine at Kaiser Permanente in San Diego, began to delve into the reasons for the high dropout rate of patients who'd been successfully losing weight in Kaiser's obesity program, he found to his surprise that a high proportion of those dropping out had histories of childhood abuse or neglect. Dr. Robert Anda, who had been doing research with the Centers for Disease Control and Prevention on the psychosocial origins of health-risk behaviors in patients at VA hospitals, heard Felitti speak about his findings, and in 1992 the two began to collaborate on the largest-scale study to date of the incidence and effects of childhood trauma, known as the Adverse Childhood Experiences (ACE) Study. According to data collected from the over 17,000 Kaiser patients in this ongoing retrospective and prospective study, adverse childhood experiences, though well concealed, are unexpectedly common, have a profound negative effect on adult health and well-being a half century later, and are a prime determinant of adult health status in the United States. The ACE Study has major implications for the healthcare professions: that all patients should be routinely screened for adverse childhood experiences; that a childhood trauma history may be very relevant to both serious illness and vague somatic complaints; and that appropriate approaches to treatment must include dealing with childhood trauma. Additional data suggest that evaluating patients for ACEs is also cost-effective. In this two-video series, Drs. Felitti and Anda, co-investigators of the ACE Study, describe the study and its ramifications. Psychiatrist Bessel van der Kolk, psychotherapist Mary Tendall, and eight adult survivors of childhood trauma add their perspectives.