There is a need for an interview-based measure to assess Prolonged Grief Disorder (PGD) included in the text revision of the fifth Diagnostic and Statistical Manual for Mental Disorder (DSM-5-TR) and 11th edition of the International Classification of Disease (ICD-11). We evaluated the psychometric properties of the Traumatic Grief Inventory-Clinician Administered (TGI-CA); a new interview measuring DSM-5-TR and ICD-11 PGD severity and probable caseness.
In 211 Dutch and 222 German bereaved adults, the: (i) factor structure, (ii) internal consistency, (iii) test-retest reliability, (iv) measurement invariance across subgroups (e.g., differing in language), (v) prevalence of probable caseness, (vi) convergent validity, and (vii) known-groups validity were examined.
Confirmatory factor analyses (CFAs) showed acceptable fit for the unidimensional model for DSM-5-TR and ICD-11 PGD. Omega values indicated good internal consistency. Test-retest reliability was high. Multi-group CFAs demonstrated configural and metric invariance for DSM-5-TR and ICD-11 PGD criteria for all group-comparisons; for some we found support for scalar invariance. Rates of probable caseness for DSM-5-TR PGD were lower than ICD-11 PGD. Optimal agreement in probable caseness was reached when increasing the number of accessory symptoms for ICD-11 PGD from 1+ to 3+. Convergent and known-groups validity was demonstrated for both criteria-sets.
The TGI-CA was developed to assess PGD severity and probable caseness. Clinical diagnostic interviews for PGD are needed.
The TGI-CA seems a reliable and valid interview for DSM-5-TR and ICD-11 PGD symptomatology. More research in larger and more diverse samples is needed to further test its psychometric properties.