Somatic symptom disorder and the role of epistemic trust, personality functioning and child abuse: Results from a population-based representative German sample.

Background: A growing body of evidence explored symptom burden of somatic symptom disorder (SSD) and its complex etiology involving psychosocial aspects. Child abuse has been linked to numerous psychopathologies including somatic symptoms as well as impaired personality functioning and disruptions in epistemic trust. This work aims to investigate personality functioning and epistemic trust in the association between child abuse and somatic symptom burden.

Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample.

Background: The Patient Health Questionnaire (PHQ-9) is a popular tool for assessing depressive symptoms in both general and clinical populations. The present study used a large representative sample of the German adult population to confirm desired psychometric functioning and to provide updated population norms.

Methods: The following psychometric properties were assessed: (i) Item characteristics (item means, standard deviations and inter-item correlations), (ii) Construct validity (correlations of the PHQ-9 sum-score with scores obtained from instruments assessing depression, anxiety and somatization (GAD-7, BSI-18), (iii) Internal consistency (coefficient omega), (iv) Factorial validity (via confirmatory factor analysis of the assumed one factorial model) as well as (v) Measurement invariance (via multi-group confirmatory factor analyses across gender, age, income and education).