Locus of control in patients with Complex Regional Pain Syndrome: a psychometric contribution

Introduction: Complex Regional Pain Syndrome (CRPS) or Sudeck's syndrome is a rare disease characterized by chronic pain that develops after a trauma and that generates deterioration in the quality of life of those who suffer from it. In this condition, the locus of control is a relevant variable with interference in adherence to treatment and as a psychological resource for coping with the disease. Objective: To design and assess the psychometric properties of a test that evaluates the internal-external locus of control in patients with CRPS Material and Methods: A total of 80 persons from Latin America and Spain with CRPS were evaluated. In addition, 92.5% were women with a mean age of 41,8 years. A test of 7 dichotomous items assessing internal and external locus of control in patients with chronic diseases was applied. Exploratory factor analysis was used to calculate validity and Cronbach's alpha test was used to estimate reliability. Results: The results indicate that the test has a unidimensional structure consisting of five items, adequate goodness-of-fit indices, and a low but acceptable reliability index. A value of 3 was also obtained as a cut-off point, so that lower scores suggest an internal locus of control and higher scores an external locus of control. Conclusions: The Locus of Control Test for Patients with Chronic Illness is valid and reliable.