Routine cerebrospinal fluid parameters as biomarkers in first-episode psychosis: A prospective observational study

In recent years, multiple studies have investigated the role of biomarkers in first-episode psychosis (FEP) to facilitate early diagnosis, disease stratification, therapeutic choice and outcome prediction. Few studies have focused on cerebrospinal fluid (CSF) investigations. In this prospective observational study, 95 FEP inpatients were followed up for one year. A lumbar puncture was performed at index admission (baseline) to study the CSF parameters (glucose, total proteins, lactate dehydrogenase [LDH], and pleocytosis). At the baseline visit, the clinical assessment included prodromal (psychotic and non-psychotic) symptoms before the psychotic outbreak and psychopathology at admission. The SCID-I was administered to obtain a clinical diagnosis at baseline and at 12 months. The relationship between prodromal and psychopathology symptoms at the baseline visit was tested with multiple linear regression. Multinomial logistic regression was also used to explore the association between CSF biomarkers and longitudinal diagnoses at follow-up (schizophrenia/schizoaffective disorder vs unipolar/bipolar depression vs other psychoses). Higher CSF glucose was associated with depressive (Standardized beta = 0.27, p = 0.041) and disorganized/concrete symptoms (Standardized beta = 0.33, p = 0.023) and lower CSF LDH was associated with prodromal symptoms (Standardized beta = -0.25, p = 0.042). Lower LDH concentrations were also associated with social withdrawal (r = -0.342, p = 0.001). CSF glucose was a predictor of the long-term diagnosis (lower CSF concentrations were associated with schizophrenia or schizoaffective disorder diagnoses [OR = 0.88, CI95%: 0.77-0.99). Our study suggests that CSF biomarkers that involve bioenergetic systems are associated with prodromal symptoms and the phenotype of psychotic disorders during the early stages of the disease.