Symptom attribution in patients with medically unexplained symptoms. A scale development and validation study

In the care of patients with medically unexplained physical symptoms (MUPS) it is important what they think about their symptoms.

To validate the psychometric properties of a symptom attribution scale in patients with MUPS and to verify its reliability.

A non-probabilistic sample of 400 male and female adult patients were interviewed in the outpatient services of a family medicine hospital, 200 with MUPS and 200 with a defined organic pathology. Each group was diagnosed with defined criteria, and a scale with content and construct validity was applied by means of principal component analysis with varimax rotation.

The scale was made up of 12 items with two factors, one of symptom psychosocial attribution and other with organic attribution. The psychosocial-origin factor showed a variance of 49.7%. The goodness-of-fit test demonstrated that the correlation matrix was adequate, and Bartlett's sphericity test indicated statistical significance (p < 0.0001); Cronbach's alpha was 0.841.

The scale showed acceptable construct validity and good reliability and stability. The implications of these results for future measurement research are discussed.