Introduction: The General health Questionnaire (GHQ) is the most popular instrument for screening psychopathology globally. It is widely used locally and has been translated into a few Nigerian languages. Research on the relationship between educational attainment and the screening ability of the English version among Nigerians is scanty.Aims: This study aims to determine the effect of educational attainment on the screening potential of 12-item General Health Questionnaire (GHQ-12) among persons in Ilupeju, Lagos.Methodology: A random sample of 399 participants was drawn from worshipers from some churches in Ilupeju in Lagos state. Socio-demographic questionnaire and the English version of the GHQ-12 were administered to the selected church members. Participants who had a GHQ score of 2 or greater than 2 and 20% of those that had a GHQ score less than 2 had Structured Clinical Interview for DSM-IV (SCID) administered to them. The data was analysed with the Statistical Package for Social Sciences, 21st edition (SPSS-21).Results: The sensitivity and specificity of the GHQ-12 among those who had secondary education or less (non-tertiary) was 82.0% and 64.2% respectively, while the sensitivity and specificity among those who had tertiary education was 89.1% and 81.4% respectively. A comparison of correctly classified and misclassified cases in both groups yielded a statistically significant difference (p=0.04). Subjects with low education were found to be 3.23 times more likely to be misclassified as false positive (95% CI 1.11-9.34, p=0.03) and 2.27 times more likely to be misclassified on the whole (95% CI 1.009-5.107, p=0.04).Conclusion: The performance of the English version of the GHQ 12 is poorer when used among persons with lower educational attainment. Standardization of the GHQ 12 for use among this demographic may need to be given research prioroty in order to improve its screening potential. A locally developed alternative in simplified English may also be considered.Keywords: GHQ 12, Education, Educational level, screening, ValidityRunning Title: Educational attainment and GHQ 1
