A comparison of two structured diagnostic interviews: CIDI and SCAN

The relationship between and the inter-rater reliability of the Composite International Diagnostic Interview (CIDI) and the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) for anxiety and depressive disorders were explored. The CIDI and the SCAN were administered by trained interviewers in counterbalanced order. A subsample of interviews was observed to determine the inter-rater reliability of the instruments. Subjects were 101 patients accepted for treatment at an Anxiety Disorders Clinic; 29 of the 101 patients participated in the inter-rater reliability study. Concordance between the instruments as measured by canonical correlation analysis was moderate for current (r=0.69, p=0.05) and for lifetime (r=0.66, p=0.05) diagnoses. Inter-rater reliability of the CIDI was perfect (overall intraclass kappa = 1.00), and of the SCAN was good (overall intraclass kappa = 0.67). It is concluded that although the two instruments made similar diagnostic distinctions, the clinical judgement involved in administering the SCAN resulted in the more moderate levels of agreement between the interviewer and observer than those found for the CIDI.