Validation of Derogatis’ Questionnaire of 90 Symtoms (SCL-90-R) in a Colombian clinical sample

Abstract

Introduction. Questionnaire of 90 symptoms (SCL- 90-R) is frequently used in the exploration of mental health, but there are no studies on its validity or sensitivity to change in Colombian clinical population. The objective is to establish the structural and psychometric properties of SCL-90-R for Colombian clinical samples, and to identify differences in relation to gender and sensitivity to change. Methodology. Longitudinal design with a three-month difference between the first and second observation. 214 patients participated (51.9 % men and 43.1 % women), with a mean age of 26 years (deviation 11.3). Both the confirmatory factorial analysis and the exploratory one were carried out to search for the best validity indexes. Instruments: SCL-90-R, and sociodemographic questionnaire and characteristics of psychotherapy. Results. Levels of reliability were identified as adequate with Cronbach alphas 0.74 to 0.90. The confirmatory factor analysis showed low goodness of fit on the indexes: Comparative goodness indexes = 0.67, Tucker- Lewis index = 0.65 and normalized adjustment index = 0.508, and approximate value of the mean square error of 0.068. The final solution of the exploratory factor analysis showed a Kaiser-Meyer-Olkin index of 0.92 and a significant result in the Bartlett sphericity test (Chi square = 3,682.9, gl = 603, p-value < 0.001). This structure included 36 items for a sample/item size ratio = 5.9 and explained 60.7 % of the total variance, with seven of the nine factors that the original questionnaire contains: depression, obsessions/compulsions, somatization, anxiety, hostility, phobic anxiety and paranoid ideation. Indices of sensitivity to change were identified for both versions. Regarding the difference according to sex, significant differences were reported in some factors, with higher scores in women; for the original questionnaire, differences were found in the anxiety factor, and on the abbreviated questionnaire in the depression factor and hostility. Conclusions. The original questionnaire reported adequate levels of reliability. The abbreviated questionnaire, generated through exploratory factor analysis, reported adequate levels of both reliability and validity. Both versions of the scale presented sensitivity to detect changes in a second evaluation moment. [Londoño NH, Agudelo DM, Martínez E, Anguila D, Aguirre DC, Arias JF. Validation of Derogatis’ Questionnaire of 90 Symtoms (SCL-90-R) in a Colombian clinical sample. MedUNAB. 2018;21(2):45-59. doi:10.29375/01237047.2807]