Exploratory factor analysis and psychometric properties of the General Health Questionnaire in Spanish adolescents.

The aim of this study was to assess the homogeneity of items, reliability as a metric indicator of global quality (internal consistency and temporal stability), and the exploratory factor structure of the General Health Questionnaire-28 (GHQ-28) in a sample of 2,010 Spanish adolescents. Mean age was 15.9 yr. (range 14-19, SD = 2.1). The test was administered twice with 20 days between responses, Answers were scored on a Likert-type scale. The internal consistency and test-retest reliabilities obtained were .93 and .94. In exploratory factor analysis, four factors explained 52.7% of the variance. These results indicated that the GHQ-28 is a psychometrically sound mental health measure in Spanish adolescents.