Reliability, factor structure, and validity of the Inventory of Complicated Grief (ICG) in a general bereaved sample in Norway

The Inventory of Complicated Grief (ICG) is the most widely used instrument to assess the severity of prolonged grief reactions after the loss of a loved one. The purpose of the present study was to investigate the psychometric properties of the Norwegian ICG by examining its reliability, factor structure, and relationships with the anxiety and depression subscales of the Brief Symptom Inventory, the Integration of Stressful Life Events Scale – Short Form, and the Work and Social Adjustment Scale. The results showed that the Norwegian ICG has high reliability (ωt = .95). Exploratory factor analysis yielded three factors (disbelief/bitterness, detachment, yearning/hallucinations) that align with factors found in previous investigations. With regard to external validity, moderate to high correlations with symptoms of anxiety and depression, difficulties with integration of the loss, and functional impairment were found. The results support the use of the ICG in bereaved populations in Norway.