Adverse Childhood Experiences Study 14-year-old study involves 17,337 adults who became members of Kaiser Permanente, a health care maintenance organization in San Diego, between 1995 and 1997. After visiting a primary care facility, they voluntarily filled out a standard medical questionnaire that included questions about their childhood. The questionnaire asked them about 10 types of child trauma: ● Three types of abuse (sexual, physical and emotional). ● Two types of neglect (physical and emotional). ● Five types of family dysfunction (having a mother who was treated violently, a household member who s an alcoholic or drug user, who s been imprisoned, or diagnosed with mental illness, or parents who are separated or divorced).