A great number of questionnaires and instruments have been developed in order to measure psychological distress/mental health problems in populations. The Survey of Level of Living in 1998 conducted by Statistics Norway used both Hopkins Symptom Checklist (SCL-25) and the Short Form 36 (SF-36), including the five-item mental health index (MHI-5). Five-item and 10-item versions of the SCL-25 have also been used in Norwegian surveys. The purpose of this study was to investigate the correlation between the various instruments, and to assess and to compare psychometric characteristics. A random sample of 9735 subjects over 15 years of age drawn from the Norwegian population received a questionnaire about their health containing SCL-25 and SF-36. Response rate was 71.9%. Reliability of the SCLs and MHI-5 were assessed by Cronbach alpha. The scores from full and abbreviated instruments were compared regarding possible instrument-specific effects of gender, age and level of education. The correlations between the instruments were calculated. The capacity of the various instruments to identify cases was assessed in terms of sensitivity, specificity, predictive values, receiver operating characteristics (ROC) and area under the curve (AUC). The reliabilities were high (Cronbach alpha>0.8). All instruments showed a significant difference in the mean scores for men and women. The correlation between the various versions of SCL ranged from 0.91 to 0.97. The correlation between the MHI-5 and the SCLs ranged from -0.76 to -0.78. The prevalence rate was 11.1% for SCL-25 scores above 1.75 and 9.7% for scores below 56 in MHI-5. AUC values indicated good screening accordance between the measures (AUC>0.92). The results suggest that the shorter versions of SCL perform almost as well as the full version. The corresponding cut-off points to the conventional 1.75 for SCL-25 are 1.85 for SCL-10 and 2.0 for SCL-5. MHI-5 correlates highly with the SCL and the AUC indicate that the instruments might replace each other in population surveys, at least when considering depression. An operational advantage of the MHI-5 over the SCL instruments is that it has been widely used not only in surveys of mental health, but also in surveys of general health.

The higher rate of depression in women is not explained by gender differences in negative life events, social support or vulnerability.

Depressive disorder is a highly prevalent condition in Europe. The major finding is the wide difference in the prevalence of depressive disorders found across the study sites.

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 buffering effect only applies to the 'externals'--those who have personality-related feelings of powerlessness and lack of control over their own lives. The 'internals' do not have the same need for social support to cope with life stressors, and have low symptom scores even when negative life events are combined with relative weak social support.