Psychometric Properties of the 7-Item Generalized Anxiety Disorder (Gad-7) in Nigerian Pregnant Women Attending Primary Health Care

AIMS: Maternal mental health is an integral component of services that should be rendered to pregnant women in addition to their physical health during their antenatal care. Mental health conditions are screened for during these visits. There is a high prevalence of anxiety disorders among this group of women. A common questionnaire used to screen for anxiety is the 7-item generalized anxiety disorder (GAD-7). However, this instrument has not been validated among pregnant women in Nigeria. We conducted research among pregnant women in Southwest Nigeria to demonstrate the psychometric properties of GAD-7 using the anxiety modules of the Mini International Neuropsychiatric Interview (MINI) as a gold standard. METHODS: We administered both GAD-7 and the anxiety module of MINI among 203 pregnant women who attended 4 randomly selected primary health centres in Southwest Nigeria. The data collected from these questionnaires were analysed using the Statistical Package for Social Sciences (SPSS). The reliability of GAD-7 was assessed with Cronbach's alpha to estimate its internal consistency. The validity of GAD-7 was examined with an assessment of its concurrent validity, sensitivity, and specificity analysis and a receiver operator characteristic curve. Using Pearson correlations, we evaluated the concurrent validity of GAD-7 and the anxiety modules of the M.I.N.I. The sensitivity, specificity, positive predictive, and negative predictive values of GAD-7 were determined with the MINI as a gold standard. The predictive accuracy was further determined from receiver operating curve analysis using the area under the curve as a standard measure. RESULTS: The internal consistency value measured by Cronbach's alpha for GAD-7 was 0.709. GAD-7 correlated minimally with the anxiety modules of MINI with a coefficient score (r) of 0.393 at a p-value of 0.01. GAD-7 has a low sensitivity & negative predictive value of 14.1% and 57.8% respectively and a high specificity & positive predictive value of 97.3% and 81.2% respectively. The area under the curve using receiver operating curve analysis was above the chance line of 0.5 with a value of 0.0557 at p < 0.05. CONCLUSION: GAD-7 is a reliable and moderately valid instrument to screen anxiety among pregnant women in Southwest Nigeria.