Psychological Distress Among Primary Care Professionals in Singapore: Repeated-Measures Analyses of Two Independent Observation Windows (HADS and GHQ-12)

Background: Healthcare professionals in Singapore’s primary care face sustained workload pressures and increasing complexity. Grounded in the Job Demands–Resources model, this study identifies demographic, clinical, and lifestyle factors associated with psychological distress among staff across two independent windows spanning the pre- and post-pandemic periods. Methods: The study was conducted among staff in National University Polyclinics (NUP) Singapore. De-identified health screening data included demographics, occupation, clinical measures, medical history, and lifestyle behaviours. Primary outcome was psychological distress, assessed across 2 distinct observation windows: the Hospital Anxiety and Depression Scale (HADS) from 2018–2022 (abnormal ≥ 8) and the General Health Questionnaire-12 (GHQ-12) from 2023–2025 (abnormal ≥ 2). Multivariate mixed-effects logistic regression identified factors associated with psychological distress while accounting for within-person clustering. Results: We analysed 3307 screening visits from 1260 staff. Within the HADS observation window (2018–2022), abnormal scores were significantly higher in 2022 compared with 2018 (OR 2.28, 95% CI 1.64–3.17). Within the GHQ-12 observation window (2023–2025), a non-significant decline in abnormal scores was observed. Older age (2018–2022: OR 0.967, 95% CI 0.948–0.987; 2023–2025: OR 0.955, 95% CI 0.928–0.983) and regular exercise (2018–2022: OR 0.724, 95% CI 0.529–0.991; 2023–2025: OR 0.357, 95% CI 0.231–0.551) were consistently associated with lower odds of distress. Medical staff had significantly lower odds of distress compared to ancillary staff in 2018–2022 (OR 0.391, 95% CI 0.207–0.739). Regular alcohol use was associated with higher distress in 2018–2022 (OR 1.56, 95% CI 1.05–2.31), while active smoking (OR 5.79, 95% CI 1.75–19.10) and family history of chronic disease (OR 2.22, 95% CI 1.28–3.87) were significant in 2023–2025. Conclusions: Older age and regular exercise were consistently associated with lower odds of psychological distress across both windows, while ancillary staff and alcohol use (HADS window), and smoking and family history of chronic disease (GHQ-12 window) were period-specific determinants. These findings support the implementation of proactive, targeted wellness initiatives alongside the routine mental health surveillance among primary care staff.