The use of the Psychosocial Index in primary care: clinimetric assessment of allostatic overload and biological correlates.

BACKGROUND: The Psychosocial Index (PSI) is a clinimetric instrument designed to integrate heterogeneous psychosocial information in medical practice. We examined whether PSI-informed assessment of allostatic overload (AO) identifies a clinically and biologically distinct subgroup in primary care. METHODS: This cross-sectional study included 430 adults aged 18-65 years recruited from a primary care centre in Türkiye. The full 55-item PSI was administered. AO status was determined by multidisciplinary consensus using participant interviews, PSI information, and observer ratings, without access to laboratory results. Sociodemographic, clinical, psychosocial, and biochemical characteristics were compared between AO-positive and AO-negative participants. Cortisol and dehydroepiandrosterone sulphate (DHEA-S) were evaluated using multivariate analysis of covariance and follow-up adjusted analyses. RESULTS: Overall, 265 participants (61.6%) were classified as AO positive. They had greater stress, psychological distress, sleep disturbance, and abnormal illness behaviour, together with lower well-being and quality of life. Biochemical data were available for 307 participants. After adjustment for age, sex, marital status, education, chronic disease, psychiatric diagnosis, and diastolic blood pressure, cortisol was 31% higher in AO-positive participants (geometric mean ratio 1.31, 95% confidence interval 1.17-1.47; P < .001). The adjusted DHEA-S difference was not statistically significant (P = .058), while C-reactive protein and metabolic parameters were similar between groups. CONCLUSIONS: PSI-informed clinimetric assessment identified a primary care subgroup with a coherent psychosocial profile and higher adjusted morning cortisol. These findings provide preliminary support for the clinical utility and biological correspondence of PSI-based AO assessment.