Reconsidering the Use of Population Health Surveys for Monitoring of Mental Health.

Monitoring of the mental health status of the population and assessment of its determinants are 2 of the most relevant pillars of public mental health, and data from population health surveys could be instrumental to support them. Although these surveys could be an important and suitable resource for these purposes, due to different limitations and challenges, they are often relegated to the background behind other data sources, such as electronic health records. These limitations and challenges include those related to measurement properties and cross-cultural validity of the tools used for the assessment of mental disorders, their degree of representativeness, and possible difficulties in the linkage with other data sources. Successfully addressing these limitations could significantly increase the potential of health surveys in the monitoring of mental disorders and ultimately maximize the impact of the relevant policies to reduce their burden at the population level. The widespread use of data from population health surveys, ideally linked to electronic health records data, would enhance the quality of the information available for research, public mental health decision-making, and ultimately addressing the growing burden of mental disorders.

Reliability and cross-country equivalence of the 8-item version of the Patient Health Questionnaire (PHQ-8) for the assessment of depression: results from 27 countries in Europe.

Background: The 8-item version of the Patient Health Questionnaire (PHQ-8) is one of the self-reported questionnaires most frequently used worldwide for the screening and severity assessment of depression. However, in some European countries its reliability is unknown, and it is unclear whether its psychometric properties vary between European countries. Therefore, the aim of this study was to assess the internal structure, reliability and cross-country equivalence of the PHQ-8 in Europe. Methods: All participants from the 27 countries included in the second wave of the European Health Interview Survey (EHIS-2) between 2014 and 2015 with complete information on the PHQ-8 were included (n = 258,888). The internal structure of the PHQ-8 was assessed using confirmatory factor analyses (CFA) for categorical items. Additionally, the reliability of the questionnaire was assessed based on the internal consistency, Item Response Theory information functions, and item-discrimination (using Graded Response Models), and the cross-country equivalence based on multi-group CFA. Findings: The PHQ-8 shows high internal consistency for all countries. The countries in which the PHQ-8 was more reliable were Romania, Bulgaria and Cyprus and less reliable were Iceland, Norway and Austria. The PHQ-8 item with highest discrimination was item 2 (feeling down, depressed, or hopeless) in 24 of the 27 countries. Measurement invariance between countries in Europe was observed from multigroup CFA at the configural, metric and scalar levels. Interpretation: The results from our study, likely the largest study to the date assessing the internal structure, reliability and cross-country comparability of a self-reported mental health assessment measure, shows that the PHQ-8 has an adequate reliability and cross-country equivalence across the 27 European countries included. These results highlight the suitability of the comparisons of the PHQ-8 scores in Europe. They could be helpful to improve the screening and severity assessment of depressive symptoms at the European level. Funding: This work was partially funded by CIBER Epidemiology and Public Health (CIBERESP) as part of the Intramural call of 2021 (ESP21PI05).