Background. A new interview measure of life events and post-traumatic stress disorder (PTSD) has been developed for children and adolescents aged 9 through 17, for use in both epidemiological and clinical studies. It includes ‘high magnitude’ events associated with PTSD as well as other ‘low magnitude’ events.

Method. The interview is designed as a module of the Child and Adolescent Psychiatric Assessment, an interviewer-based interview conducted with parent and child separately by trained lay interviewers. The module includes: (1) questions about a wide range of events; (2) a screen for key PTSD symptoms (painful recall, avoidance, hypervigilance); and (3) a detailed interview on all PTSD symptoms, including onset, duration, severity and co-morbidity. A test–retest reliability study was conducted with 58 parents and children, who were interviewed twice by different interviewers.

Results. Intraclass correlations were 0·72 (child) and 0·83 (parent) for high magnitude events, and 0·62 (child) and 0·58 (parent) for low magnitude events. Kappa coefficients ranged from high for violence and sexual abuse to low for child reports of serious accidents and natural disasters. The reliability of the PTSD screen symptoms was fair to excellent (κ=0·40–0·79), and reliability of PTSD symptoms in those who passed the screen was excellent (ICC=0·94–0·99). Compared with a general population sample (N=1015), the clinic-referred subjects and their parents were twice as likely to report a traumatic event and, depending on the event, up to 25 times as likely to report symptoms of PTSD.

Conclusions. The results support the reliability and discriminant validity of the measure.