Factor structure, Validity, and Reliability of General Health Questionnaire (GHQ-28) in Iranian Adolescents

Investigation of Factor structure, validity, and reliability of general health questionnaire (GHQ) in Iranian adolescents was the purpose of present study. Study design was descriptive and 1497 high school students (789 girls and 708 boys) from Qom, Damghan, and Bojnoord cities were selected using cluster sampling. General Health Questionnaire (GHQ) as the main questionnaire, and General Anxiety Index (GAD-7) and Personal Wellbeing Index- School Children (PWI-SC) were used to assess convergent validity. Results of explanatory and parallel factor analysis revealed three factors predicting 36.36 present of variance in scores of general health questionnaire. Indexes of confirmatory factor analysis showed good fitness of three-factor model and in general 8 questions were removed. Correlation between three dimensions of 20 item general health questionnaire with main questionnaire was strong and significant, with GAD-7 was moderate and with PWI-SC was strong (moderate for depression dimension). Cronbach's alpha value for dimensions and total score of questionnaire were acceptable and test-retest coefficients were strong. 20 items general health questionnaire with vitality and energy, anxiety and somatic symptoms, and depression was obtained.