Validating the Patient Health Questionnaire-9 (PHQ-9) for screening of depression in Tanzania

Major depression has a significant impact on years lived with disability (YLD) globally. In resource-limited countries, depression may accompany daily challenges of economic security that people face, hence there is a critical need to develop depression screening tools at primary levels of health care. The overall goal of the study is to validate the PHQ-9 in Tanzania.

A validation study was conducted from August to October 2014 among adults accessing primary health care at public clinics in Dar es Salaam. The Mini-International Neuropsychiatric Interview (MINI) was used as the gold standard for current major depressive episode.

Among 180 patients recruited, six were not included in the analysis since the PHQ-9 and MINI assessments were conducted more than two weeks apart (n=174). The PHQ-9 demonstrated reasonable reliability in this setting (α=0.83). Evidence for construct validity was observed through expected associations with female gender (r=0.16, p=0.04) and food insecurity (r=0.30, p<0.0001). Receiver Operating Characteristic analysis demonstrated good overall accuracy of the PHQ-9 (AOC=0.87, 95%CI: 0.77, 0.96). The optimal cut-off score in this population was 9, with a sensitivity of 78% and specificity of 87%.

The study sample is from a primary health care setting, hence the findings may have some limited generalizability at the community level.

The PHQ-9 demonstrated reliability and validity among adults accessing primary health care in Dar es Salaam, indicating that it can serve as a useful tool in identifying patients with depression in primary care clinics in Tanzania and similar settings.