The definition of case is a core issue in psychiatric epidemiology. Psychiatric symptom screening scales have been extensively used in population studies for many decades. Structured diagnostic interviews have become available during recent years to give exact diagnoses through carefully undertaken procedures. The aim of this article was to assess how well the Hopkins Symptom Checklist-25 (HSCL-25) predicted cases by the Composite International Diagnostic Interview (CIDI), and find the optimal cut-offs on the HSCL-25 for each diagnosis and gender. Characteristics of concordant and discordant cases were explored. In a Norwegian two-stage survey mental health problems were measured by the HSCL-25 and the CIDI. Only 46% of the present CIDI diagnoses were predicted by the HSCL-25. Comorbidity between CIDI diagnoses was found more than four times as often in the concordant cases (case agreed upon by both instruments) than in the discordant CIDI cases. Concordant cases had more depression and panic/generalized anxiety disorders. Neither the anxiety nor the depression subscales improved the prediction of anxiety or depression. The receiver operating characteristic (ROC) curves confirmed that the HSCL-25 gave best information about depression. Except for phobia it predicted best for men. Optimal HSCL-25 cut-off was 1.67 for men and 1.75 for women. Of the discordant HSCL-25 cases, one-third reported no symptoms in the CIDI, one-third reported symptoms in the CIDI anxiety module, and the rest had symptoms spread across the modules. With the exception of depression, the HSCL-25 was insufficient to select individuals for further investigation of diagnosis. The two instruments to a large extent identified different cases. Either the HSCL-25 is a very imperfect indicator of the chosen CIDI diagnoses, or the dimensions of mental illness measured by each of the instruments are different and clearly only partly overlapping.

The findings provide evidence of psychiatric illness being a rising and major health problem, but the role of recall bias must be further investigated.

In previous analyses of data from the present general population study we found that screening of anxiety and depression symptoms by the Hopkins Symptom Checklist-25 (HSCL-25) and diagnostic classification by the Composite International 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 unspecific measure of distress. The HSCL-25 and the illness indicators data were collected in a stage I random individual population sample above 18 years during 1989-1991 (N = 1879, response rate 74%), the CIDI data were collected 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 HSCL-25 had significantly more illness indicators than diagnostic cases by the CIDI. Cases agreed upon with both instruments had the most illness indicators, cases agreed upon only by the CIDI had the least. Diagnoses give information about help eventually needed, the HSCL-25 distress measure expresses 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 evaluation of needs is involved, using an instrument picking up both classification and distress would be the best choice. Given our positive experience with interviewing with the CIDI, a CIDI improved to be more sensitive to how much distress a certain diagnosis exerts on the individual would be a good choice.

In a population study we analysed psychiatric help-seeking directed to general practitioners (GPs) and looked at who was referred to and received treatment from psychiatrists or psychologists. A random sample of 2015 persons were interviewed on a large number of variables, of which five groups were used in logistic regression analysis to find what accounted for (1) help-seeking addressed to GPs, (2) prior (not during the last 12 months) referral from GPs to, and treatment from, a psychiatrist or psychologist, and (3) current specialist referral/treatment (referral to/treatment from a psychiatrist/psychologist in the last 12 months). A total of 38 variables were covered in the areas of demographics, social support, life events and general well-being, and mental health (HSCL-25), with six personality-related variables. The conclusions are: (1) The strongest predictor of former and current help-seeking was high current symptom rating (HSCL-25). (2) Demographic variables played a limited role in explaining help-seeking. (3) Personality-related variables played a more important role in the referral/treatment groups than most demographic variables. Compared with those not being referred, people currently seeing or having seen a psychiatrist/psychologist described themselves as easily worried, but at the same time having an attitude of speaking out and of not accepting a below-par life situation.

Help-seeking for emotional problems addressed to priests was compared with help-seeking addressed to general practitioners (GPs), psychiatrists and psychologists in two demographically different areas of Norway. Only small differences were found between the rural and the urban area, and a substantial proportion of people contacted priests for personal/emotional problems. This contact was not related to dissatisfaction with the mental health system, and we found no evidence for a "religiosity gap" between mental health professionals, on the one hand, and people contacting priests, on the other. People contacting priests also had a stronger general willingness to seek help from other professionals compared to the general population. In both the rural and urban areas, seeking help from priests because of mental problems was related to having experienced a personal loss (death of a spouse, separation, divorce), in addition to having a religious commitment.