Allostatic load in psychiatry: a systematic review and meta-analysis

The pathophysiology of psychiatric disorders is complex and involves multiple biological systems. The allostatic load (AL) model offers a framework to capture this multisystem dysregulation by assessing biomarkers that reflect the activity of different physiological systems. This systematic review aimed to summarise current literature on the association between AL and psychiatric disorders. The databases Medline (Ovid), PsycINFO, Ovid Emcare, CINAHL, Cochrane, and Scopus were systematically searched from inception to July 2025. A total of twenty-eight studies were included in the systematic review, and sixteen were eligible for meta-analysis. We found that individuals with a psychiatric disorder demonstrated elevated AL compared to healthy controls (HCs). Furthermore, the meta-analyses revealed an overall standardised mean difference of the between-group meta-analysis, which demonstrated higher AL in individuals with schizophrenia and first-episode psychosis (SMD: 0.97; 95% CI: 0.76, 1.18; p < .0001) compared to HCs. In contrast, no significant difference in AL was observed for individuals with major depressive disorder (SMD: 0.07; 95% CI: -0.23; 0.37; p = 0.67). In conclusion, the AL model may offer a valuable tool for evaluating the impact of chronic stress across various biological systems. This approach can be applied to the early intervention of the core pathophysiology as well as systemic comorbidities that are common among those with psychiatric symptoms.