Eye-Movements Deficits In Schizophrenia: A Metanalysis Of Evidence

Introduction Although eye-movement disorders are one of the most replicated deficits in the psychiatric literature, the strong heterogeneity of results is still an unexplained issue that could be effectively addressed with a quantitative review of evidence. Objectives For this reason, a large-scale metanalytic study comprising more than 200 studies was conducted to analyse the presence of eye-movement deficits in schizophrenia patients, as compared to healthy controls. Methods To this aim, saccadic eye movements were grouped based on the type of task required (e.g., standard, predictive) and the quantification method used (e.g., number, duration, amplitude). For each sub-group separate meta-analysis were computed. Cohen’s d was used as measure of effect size. Risk of bias within and between studies and heterogeneity were also analysed. Results indicated low Cohen’s d with the exception of the number of correct antisaccades – where schizophrenia patients reportedless correct anti-saccadesthan healthy controls - and antisaccades error rate – where schizophrenia patients reported a higher number of errors than healthy controls. Conclusions Antisaccades emerged as better suited to differentiate between patients and healthy controls, thus making them the most promising candidate as a possible biomarker for schizophrenia.