L'espace vecu and Its Perturbations in Schizophrenia: Systematic Review and Meta-analysis of Altered Body-Centric Metrics-Personal and Peripersonal Space

Subtle distortions of the experience of lived space have long been associated with schizophrenia. Although a body-centric transformation of space is considered an essential component of anomalous subjective experience in schizophrenia, its impact on the 2 major body-centric spatial constructs, that is, personal space (PS) and peripersonal space (PPS), is still not clear. This systematic review and meta-analysis have been set up to: (1) summarize the evidence on putative extensional differences of PS and PPS in schizophrenia as compared with controls, and (2) evaluate the quality and the limitations of available studies on the topic. Four electronic literature databases (MEDLINE, EMBASE, PsychINFO, and CINAHL) were searched with the keywords "Personal space OR Interpersonal distance AND Schizophrenia," "Peripersonal space AND Schizophrenia" from inception until December 31, 2023, resulting in 15 studies on PS and 5 studies on PPS included in this systematic review. The 12 studies on PS included in the meta-analysis revealed that individuals with a diagnosis of schizophrenia place a larger interpersonal distance from the stimuli than controls, with a moderate effect size in both the fixed-effect model (Hedges' g = 0.558 [95% confidence interval, CI: 0.445-0.671]; z = 9.67; P < 0.0001) and the random effects model (0.547 [0.294-0.799]; z = 4.77; P = 0.0006). The 5 studies included in the meta-analysis on PPS showed that individuals with a diagnosis of schizophrenia exhibit a narrower PPS than the controls at the fixed-effect (Hedges' g = 1.043 [95%CI: .739-1.348]; z = 6.72; P < .0001), but not at the random effects model (1.318 [-0.721 to 3.359]; z = 1.79; P = .147). Heterogeneity was substantial in both meta-analyses. Overall, the findings indicate that both body-centered space constructs (PS and PPS) are affected in schizophrenia, with an enlargement PS and a reduction PPS, thereby supporting the distinction of these constructs. These modifications cohere with the subjective transformation of the lived space (aka espace v & eacute;cu) reported in classical psychopathology and may be promising, neurodevelopmentally grounded, biomarkers of vulnerability to schizophrenia and its spectrum conditions.