Concordance of DSM-IV Axis I and II diagnoses by personal and informant's interview

The validity and reliability of using psychological autopsies to diagnose a psychiatric disorder is a critical issue. Therefore, interrater and test-retest reliability of the Structured Clinical Interview for DSM-IV Axis I and Personality Disorders and the usefulness of these instruments for the psychological autopsy method were investigated. Diagnoses by informant's interview were compared with diagnoses generated by a personal interview of 35 persons. Interrater reliability and test-retest reliability were assessed in 33 and 29 persons, respectively. Chi-square analysis, kappa and intraclass correlation coefficients, and Kendall's tau were used to determine agreement of diagnoses. Kappa coefficients were above 0.84 for substance-related disorders, mood disorders, and anxiety and adjustment disorders, and above 0.65 for Axis II disorders for interrater and test-retest reliability. Agreement by personal and relative's interview generated kappa coefficients above 0.79 for most Axis I and above 0.65 for most personality disorder diagnoses; Kendall's tau for dimensional individual personality disorder scores ranged from 0.22 to 0.72. Despite of a small number of psychiatric disorders in the selected population, the present results provide support for the validity of most diagnoses obtained through the best-estimate method using the Structured Clinical Interview for DSM-IV Axis I and Personality Disorders. This instrument can be recommended as a tool for the psychological autopsy procedure in post-mortem research.