Abstract
Background
Clinical staging models describe where an individual exists on a continuum from asymptomatic at‐risk states (Stage 0) through to established late‐stage disease (Stage 4). We applied this framework to systematically assess evidence for any associations between objectively assessed cardio‐respiratory fitness (CRF) and stage of psychosis.
Method
Nine electronic databases were searched for relevant publications from inception until October 31st, 2019. Pooled effect sizes (Hedges’s g and 95% confidence intervals (95% CI)) were estimated for differences in CRF for studies that reported mean oxygen uptake (max, peak or predicted VO2 in ml/kg/min).
Results
Thirty‐eight studies were eligible. Findings indicated that sub‐optimal CRF can be present at Stage 0 and 1. Meta‐analyses of 22 studies demonstrated that CRF was significantly reduced in individuals classified between Stages 1 and 4 compared with matched or general population controls (g ‐.93; 95% CI ‐1.14, ‐.71). Mean VO2 was decreased by 28% in Stage 4 compared with Stage 1 (34.1 vs. 24.66 ml/kg/min); the largest effect size for CRF reduction was reported between Stage 2 and 3 (g ‐1.16; 95% CI ‐1.31, ‐1.03).
Conclusions
Although not identifying direct causal links between clinical stage and CRF, using this framework may enhance understanding of co‐associations between mental and physical health markers across the entire spectrum of psychosis. Limitations include lack of research on CRF in Stage 0 and 1 alongside problems determining stage in some studies. However, impaired CRF is reported in emerging psychosis, supporting calls that early intervention programs should address both mental and physical well‐being.