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.

Smoking has been found to be associated with depression. Biologic hypotheses support causation in both directions. This study examined the association between cigarette smoking and a subsequent first depression. In 1990, 2,014 adults in Norway were interviewed about their lifestyle and mental health. A 2001 reinterview by trained interviewers defined the study cohort of 1,190 participants. The cases were those who experienced a first depression whose onset was estimated to occur during the follow-up period, based on retrospective assessment by the Composite International Diagnostic Interview (International Classification of Diseases, Tenth Revision). Cox regression was used to estimate the hazard rate of depression during follow-up. Alternative explanations for a direct causal influence from smoking on subsequent depression were assessed, and a sensitivity analysis was performed. The risk of depression was four times as high for heavy smokers compared with never smokers. A dose-response relation with an increasing hazard for past smokers and for an increasing number of cigarettes smoked per day for current smokers was found. Similarly, increasing smoking time was associated with increasing risk. Failure of other plausible alternatives to explain the observed association between smoking and depression might reflect a direct causal influence of smoking on depression.

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

BackgroundConsistent with global trends, the prevalence of obesity is increasing among Norwegian adults. This study aimed to investigate individual trends in BMI (kg/m2) by age, gender, and socio-economic status over an 11-year period.MethodsA cohort of 1169 adults (n = 581 men; n = 588 women) self-reported BMI during a general health interview twice administered in two regions in Norway.ResultsAverage BMI increased significantly from 23.7 (SD = 3.4) to 25.4 (SD = 3.8), with equivalent increases for both genders. Proportion of obesity (BMI ≥ 30) increased from 4% to 11% for women and 5% to 13% for men. Of those already classified as overweight or obese in 1990, 68% had gained additional weight 10 years later, by an average increase of 2.6 BMI units. The greatest amount of weight gain occurred for the youngest adults (aged 20–29 years). Age-adjusted general linear models revealed that in 1990, women with a lower level of education had a significantly greater BMI than more educated women. In both 1990 and 2001, rural men with the highest level of household income had a greater BMI than rural men earning less income. Weight gain occurred across all education and income brackets, with no differential associations between SES strata and changes in BMI for either gender or region.ConclusionResults demonstrated significant yet gender-equivalent increases in BMI over an 11-year period within this cohort of Norwegian adults. Whereas socio-economic status exerted minimal influence on changes in BMI over time, young adulthood appeared to be a critical time period at which accelerated weight gain occurred.

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.