The Childhood Trauma Study’s computer-assisted diagnostic interview was completed via telephone. Interviewers completed an extensive training process supervised by an experienced clinical psychologist. Data reported herein on lifetime MDD were obtained using a modified section of the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA), for which reliability30 and validity31 are well established. The assessment of lifetime DSM-IV PTSD was modified from the National Comorbidity Survey4 interview, which itself was derived from the Revised Diagnostic Interview Schedule.32 The National Comorbidity Survey assessment, for which excellent psychometric properties have been reported,4 first asks respondents whether they had ever experienced a series of traumatic events (Table 1). To protect confidentiality, respondents looked at a numbered list of brief event descriptions contained in a booklet of materials mailed in advance of the interview. Each event was then queried by number (eg, “Did event number 1 ever happen to you?”). Respondents were then asked which event was most disturbing, and the assessment of lifetime PTSD focused on the identified event. Additional demographic information and DSM-IV diagnostic data were also obtained using interview sections modified
