Validation of screening instruments for common mental disorders and suicide risk in south African primary care...

In South Africa, there is limited mental health infrastructure and resources. Valid screening tools are needed to facilitate identification and linkage to care. We evaluated the performance of Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Primary Care Post Traumatic Stress Disorder Screen for DSM-5 (PC-PTSD-5), and the Columbia Suicide Severity Rating Scale (C-SSRS) among adults in South Africa against a diagnostic gold standard.

Adults present at healthcare facilities were screened with the PHQ-9, GAD-7, PC-PTSD-5, and the C-SSRS. Nurses used a structured diagnostic interview to identify depression, anxiety, panic disorder, PTSD and elevated suicide risk. We assessed the internal consistency, criterion validity, and the sensitivity and specificity of these tools.

Of the 1885 participants, the prevalence of common mental disorders and suicide risk was 24.4 % and 14.9 %, respectively. The PHQ-9, GAD-7, and PC-PTSD-5 showed good internal consistency (0.80-0.89). All screeners demonstrated good criterion validity. For depression, a cut-off of ≥5 on the PHQ-9 yielded sensitivity of 84.24 %, while ≥10 yielded sensitivity of 48.77 %. For anxiety, the GAD-7 performed similarly. A cut-off of ≥4 on the PC-PTSD yielded sensitivity of 61.96 %. The C-SSRS yielded lower sensitivity than expected.

The prevalence data is not generalizable to the larger South African adult population given the use of a targeted, healthcare facility-based sampling and recruitment strategy.

The performance of the PHQ-9, GAD-7, and PC-PTSD-5 demonstrated good internal consistency and criterion validity, though sensitivity and specificity trade-offs were enhanced with lower cut-offs. Further research into suicide risk screening is warranted.