The Posttraumatic Growth Inventory: factor structure and invariance among persons with chronic diseases

The Posttraumatic Growth Inventory (PTGI) assesses positive changes after a traumatic or serious life crisis. However, there are differing views regarding its factor structure and little understanding if it captures the positive changes experienced among individuals diagnosed with a chronic disease. Using confirmatory factor analysis (CFA), the proposed five-factor structure and measurement invariance of the PTGI was examined using two chronic illness samples: arthritis and inflammatory bowel disease (IBD).

Individuals diagnosed with arthritis (n = 301) or IBD (n = 544) recruited from the community and the Internet completed the PTGI. Using a pooled sample, CFA tested five hypothesized models of the underlying factors structure of the PTGI. A stepwise procedure for testing the measurement invariance across the two groups evaluated the factor structure, factorial invariance, and latent mean invariance.

Using the pooled sample, the CFA supported the hypothesized five-factor model, revealing the PTGI is multidimensional. Multigroup CFA supported invariance of the PTGI across the two groups although there were significant differences in latent means.

The findings support that the PTGI assesses five related dimensions of PTG and that different chronic disease groups experience different types of positive changes. PTG may therefore be relevant as a meaningful treatment goal for people with chronic diseases as it is for people affected by other traumatic events.