The Importance of Cerebrospinal Fluid Investigation in First-episode Psychosis

Despite being a reliable first-hand source of data on neuronal pathology, cerebrospinal fluid (CSF) analysis remains an often-overlooked evaluation method in first-episode psychosis (FEP). In this paper, we begin by discussing the current role of CSF testing during FEP evaluation in clinical practice. Given that anti-N-methyl-D-aspartate receptor encephalitis presents with a clinical picture indistinguishable from FEP in >85% of cases, we debate the importance of testing for CSF neuronal antibodies in at least a subset of patients. Then, we continue by reviewing the most important recent studies which sought to identify potential CSF biomarkers in FEP caused by a primary psychiatric disorder. By circumventing traditional psychiatric classifications, characteristic biomarker profiles have the potential to become integral components of early diagnosis, disease stratification, treatment choice, and outcome prediction. Along these lines, we aim to provide an updated perspective on the importance of CSF investigation in FEP.