Factor structure and reliability of the 12-item Sinhala version of General Health Questionnaire

Introduction: The General Health Questionnaire (GHQ) is widely used to detect common psychiatric disorders. Even though the GHQ 12 has been validated for many countries, psychometric properties in relation to the Sinhala speaking Sri Lankan population lack conclusive evidence. Objective: To determine the factor structure and the reliability of the Sinhala version of GHQ 12. Methods: This was a descriptive study including 385 patients with in the age range of 18 to 75 years, attending the Out Patient Department of Colombo North Teaching Hospital, Ragama, Sri Lanka, between June 2009 to September 2010. Sinhala version of GHQ-12 was completed by the participants. Each item of the GHQ was rated on a four-point scale (0-1-2-3). Factor analyses were performed by applying Generalized Least Squares method using oblimin rotation. The internal consistency was assessed by calculating Cronbach's a coefficient. Results: Median age of the study population was 32.5 years (IQR = 21years) and the median GHQ score was 9 (IQR= 7). The GHQ 12 yielded two factor solutions. Factor I (Depression and Anxiety) accounted for 88% of the total explained variance and Factor II (Social dysfunction) 12%. Forty five percent (45%) of the total variance could be explained by the two extracted factors. There was a clear distinction between the items that loaded on the two factors. The correlation coefficient between the factors I and II was 0.65. The Cronbach's alpha of GHQ 12 was 0.88, which indicated satisfactory internal consistency. Conclusions: GHQ 12 displays adequate reliability and validity for use in the Sinhala speaking primary care attendees of Colombo North Teaching Hospital for assessing psychiatric disorders.