Diagnosing depressive disorders in patients with alcohol and drug problems: a comparison of the SADS-L and the DIS.

The DIS and the SADS-L diagnostic procedures occupy an important position in psychiatric research. We compared these procedures for assessing depressive disorders in patients with substance abuse problems. The two instruments agreed poorly, and the SADS-L produced a considerably higher proportion of cases than the DIS. A number of factors were examined to determine their influence on the agreement obtained for Major Depression. These factors included (1) recency of the disorder, (2) the primary/secondary distinction, (3) clinical experience of the DIS interviewers, (4) numerous subject characteristics and (5) the DIS procedure for differentiating organic from non-organic affective symptomatology, which relies on subjects' attributions of the cause of symptoms. The first four factors did not influence agreement. However, removal of the influence of the fifth factor did increase agreement between the instruments appreciably. Validation evidence favored the SADS-L, although not definitively. Implications of the findings are discussed.