Validation of the Brief Inventory of Symptoms (BSI-18) among mexican women diagnosed with breast cancer

Abstract

Distress is an unpleasant emotional experience that can affect the coping and course of an oncological disease. The Brief Inventory of Symptoms (BSI-18) is frequently used in cancer patients to measure distress. However, its factorial structure is not well established, and its metric properties have not been studied with Mexican samples. The present research aims to study the distribution, discriminability and homogeneity of BSI-18 items, estimate the internal consistency of the BSI-18, determine its factorial structure, and calculate the convergent, discriminant validity and internal consistency of its factors. An intentional sample of 203 women with breast cancer on oncological treatment was collected. All of them were adults treated in the city of Monterrey, Mexico. All BSI-18 items were discriminative and consistent. Their distributions showed higher concentration in low values. The internal consistency of the scale was high (Cronbach’s α = .888). The model of a general distress factor with three hierarchical factors (depression, sympathetic anxiety symptoms and vasovagalanxiety symptoms) showed the best goodness-of-fit properties. Also, its factors had the best propertiesof convergent validity and internal consistency. In addition, this model allowed to overcome theproblems of discriminant validity between the factors. We concluded that, in the studied population ofwomen diagnosed with cancer, all items of the BSI-18 can be retained, and scale was consistent andvalid from a hierarchical model of three factors.