Reliability and factor structure of the Portuguese version of Self-Reporting Questionnaire

The Self-Reporting Questionnaire is a screening instrument devised by the WHO to identify minor psychiatric morbidity in primary care settings and the community in developing countries. It has already been widely used although its psychometric properties are not yet completely explained. The present article describes the following properties of the Portuguese version of the SRQ-20: a) coefficients of internal consistency; b) inter-rater reliability coefficients, and c) a factor analysis. Internal consistency, measured by the KD20 method, was 0.81. The intra-class correlation coefficient obtained from simultaneous scoring of four interviewers was 0.96, considerably high, as expected from a structured instrument. In the factor analysis four main factors accounted for 41% of the total item variance, and they could be reasonably identified as Decreased Energy, Somatic symptoms, Depressive mood and Depressive thoughts.