Measurement invariance of the Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder scale (GAD-7) across four European countries during the COVID-19 pandemic.

BACKGROUND: The Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder scale (GAD-7) are self-report measures of major depressive disorder and generalised anxiety disorder. The primary aim of this study was to test for differential item functioning (DIF) on the PHQ-9 and GAD-7 items based on age, sex (males and females), and country. METHOD: Data from nationally representative surveys in UK, Ireland, Spain, and Italy (combined N = 6,054) were used to fit confirmatory factor analytic and multiple-indictor multiple-causes models. RESULTS: Spain and Italy had higher latent variable means than the UK and Ireland for both anxiety and depression, but there was no evidence for differential items functioning. CONCLUSIONS: The PHQ-9 and GAD-7 scores were found to be unidimensional, reliable, and largely free of DIF in data from four large nationally representative samples of the general population in the UK, Ireland, Italy and Spain.

Monitoring the psychological, social, and economic impact of the COVID-19 pandemic in the population: Context, design and conduct of the longitudinal COVID-19 psychological research consortium (C19PRC) study.

OBJECTIVES: The C19PRC study aims to assess the impact of the COVID-19 pandemic in the adult population of the UK, Republic of Ireland, and Spain. This paper describes the conduct of the first two waves of the UK survey (the "parent" strand of the Consortium) during March-April 2020. METHODS: A longitudinal, internet panel survey was designed to assess: (1) COVID-19 related knowledge, attitudes, and behaviors; (2) the occurrence of common mental health disorders as well as the role of (3) psychological factors and (4) social and political attitudes, in influencing the public's response to the pandemic. Quota sampling (age, sex, and household income) was used to recruit a nationally representative sample of adults. RESULTS: Two thousand and twenty five adults were recruited at baseline, and 1406 were followed-up one-month later (69.4% retention rate). The baseline sample was representative of the UK population in relation to economic activity, ethnicity, and household composition. Attrition was predicted by key socio-demographic characteristics, and an inverse probability weighting procedure was employed to ensure the follow-up sample was representative of the baseline sample. CONCLUSION: The C19PRC study data has strong generalizability to facilitate and stimulate interdisciplinary research on important public health questions relating to the COVID-19 pandemic.

Context, design and conduct of the longitudinal COVID-19 psychological research consortium study-wave 3.

OBJECTIVES: The COVID-19 Psychological Research Consortium (C19PRC) Study aims to assess the impact of the COVID-19 pandemic in the adult population in multiple countries. This paper describes the third wave of the UK survey (the 'parent' strand of the Consortium) during July-August 2020. METHODS: Adults (N = 2025) who participated in the baseline and/or first follow-up surveys were reinvited to participate in this survey, which assessed: (1) COVID-19 related knowledge, attitudes, and behaviours; (2) the occurrence of common mental disorders; as well as the role of (3) psychological factors and (4) social and political attitudes, in influencing the public's response to the pandemic. Weights were calculated using a survey raking algorithm to ensure that the cross-sectional sample is nationally representative in terms of gender, age, and household income, and representative of the baseline sample characteristics for household composition, ethnicity, urbanicity and born/raised in UK. RESULTS: 1166 adults (57.6% of baseline participants) provided full interviews at Wave 3. The raking procedure successfully re-balanced the cross-sectional sample to within 1% of population estimates across selected socio-demographic characteristics. CONCLUSION: This paper demonstrates the strength of the C19PRC Study data to facilitate and stimulate interdisciplinary research addressing important public health questions relating to the COVID-19 pandemic.

Sharing data to better understand one of the world's most significant shared experiences: data resource profile of the longitudinal COVID-19 psychological research consortium (C19PRC) study.

This paper serves to alert IJPDS readers to the availability of a major new longitudinal survey data resource, the COVID-19 Psychological Research Consortium (C19PRC) Study, which is being released for secondary use via the Open Science Framework. The C19PRC Study is a rich and detailed dataset that provides a convenient and valuable foundation from which to study the social, political, and health status of European adults during an unprecedented time of change as a direct result of the COVID-19 pandemic and Brexit. Here, we provide an overview of the C19PRC Study design, with the purpose of stimulating interest about the study among social scientists and maximising use of this resource.