Aberrant Functional Whole-Brain Network Architecture in Patients With Schizophrenia: A Meta-analysis

Abstract

Findings from multiple lines of research provide evidence of aberrant functional brain connectivity in schizophrenia. By using graph-analytical measures, recent studies indicate that patients with schizophrenia exhibit changes in the organizational principles of whole-brain networks and that these changes relate to cognitive symptoms. However, there has not been a systematic investigation of functional brain network changes in schizophrenia to test the consistency of these changes across multiple studies. A comprehensive literature search was conducted to identify all available functional graph-analytical studies in patients with schizophrenia. Effect size measures were derived from each study and entered in a random-effects meta-analytical model. All models were tested for effects of potential moderator variables as well as for the presence of publication bias. The results of a total of n = 13 functional neuroimaging studies indicated that brain networks in patients with schizophrenia exhibit significant decreases in measures of local organization (g = -0.56, P = .02) and significant decreases in small-worldness (g = -0.65, P = .01) whereas global short communication paths seemed to be preserved (g = 0.26, P = .32). There was no evidence for a publication bias or moderator effects. The present meta- analysis demonstrates significant changes in whole brain network architecture associated with schizophrenia across studies.

Keywords: cognition; connectivity; graph analysis; meta-analysis; schizophrenia.

Fig. 1.

Effect sizes of studies reporting changes in functional brain networks in patients with schizophrenia as indicated by measures of global short communication paths (minimal path length, global efficiency), local organization (clustering coefficient, local efficiency) and small-worldness. Summary effect sizes of meta-analyses are presented for cases with n ≥ 4 using bar plots and individual studies’ effect sizes are plotted as single points. For each meta-analysis the number of available studies is indicated below each bar plot. Negative values on the y-axis represent lower graph-analytical parameters for patients compared to healthy controls. Error-bars represent the upper bound of the 95% CI. *Indicates significance on the level of P < .05.