The CIDI was administered by more than 40 research assistants that have been trained, including psychologists, nurses, or residents in psychiatry. Research assistants received 1 week of training by the fieldwork coordinator, and were certified to conduct assessments following approval of audiotapes of at least two complete interviews. Question wording and probing behavior of interviewers was constantly monitored by checking a random selection of about 10% of all taped interviews.