Psychometric evaluation of the Swedish Traumatic Grief Inventory Self-Report Plus (TGI-SR+) in bereaved parents

Abstract

The International Classification of Diseases Eleventh Edition (ICD-11), and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), now include prolonged grief disorder (PGD). Since criteria for PGD in both classification systems differ from prior proposed grief disorders and each other, the validation of a single instrument to screen for prolonged grief (PG) symptoms of both new diagnoses is critical for bereavement research and care. Therefore, we evaluated the psychometric properties of the Swedish version of the Traumatic Grief Inventory Self-Report Plus (TGI-SR+). Two-hundred and forty-eight bereaved parents completed questions about sociodemographic and loss-related variables, the TGI-SR+, and symptom measures of post-traumatic stress (PTS), depression and an older measure of PG symptoms, the Prolonged Grief Disorder-13 (PG-13). Confirmatory factor analyses showed that a one-factor model best fit DSM-5-TR and ICD-11 PG symptoms and the analyses of the internal consistency and inter-item correlations showed that these symptoms could be reliably assessed. In support of convergent validity, DSM-5-TR and ICD-11 PG symptoms correlated with symptoms of PTS, depression and PG assessed with the PG-13. In support of known-groups validity, DSM-5-TR and ICD-11 PG symptoms were higher among lower educated (vs. higher educated) participants and related negatively to time since loss. ROC analyses showed optimal cut-off score of ≥71 and ≥72 to determine probable caseness for DSM-5-TR and ICD-11 PGD, respectively. Results support the reliability and validity of the Swedish TGI-SR+ as a screening instrument for PG in research and bereavement care.