The meaning and significance of caseness: the Hopkins Symptom Checklist-25and the Composite International Diagnostic Interview II

In previous analyses of data from the present general population study we f ound that screening of anxiety and depression symptoms by the Hopkins Sympt om Checklist-25 (HSCL-25) and diagnostic classification by the Composite In ternational Diagnostic Interview (CIDI) identified the same amount of cases , but agreed in only half of them. In this paper we compared and validated the screening cases with the classificatory cases by the use of medication, loss of functioning and help seeking (illness indicators). We thought that the CIDI cases would have more illness indicators, because they reflected diagnoses, "true illness", in contrast to the HSCL-25, which was a more uns pecific measure of distress. The HSCL-25 and the illness indicators data we re collected in a stage I random individual population sample above 18 year s during 1989-1991 (N = 1879, response rate 74%), the CIDI data were collec ted in a selected stage II, (N = 606, response rate 77%). The stage II data were weighted to represent the population sample. Screening cases by the H SCL-25 had significantly more illness indicators than diagnostic cases by t he CIDI. Cases agreed upon with both instruments had the most illness indic ators, cases agreed upon only by the CIDI had the least. Diagnoses give inf ormation about help eventually needed, the HSCL-25 distress measure express es more the urgency with which it is needed. The choice between the HSCL-25 and the CIDI would depend on the aim and the resources of the study. If ev aluation of needs is involved, using an instrument picking up both classifi cation and distress would be the best choice. Given our positive experience with interviewing with the CIDI, a CIDI improved to be more sensitive to h ow much distress a certain diagnosis exerts on the individual would be a go od choice.