Neurofilament Light Chains and Cognitive Impairment in Chronic Psychiatric Disease

Validation of Serum Neurofilament Light Chain as a Biomarker to Differentiate Cognitive Impairment From Neurodegenerative or Psychiatric Diseases

The validation of biomarkers allowing the discrimination of cognitive and behavioral disorders of psychiatric origin from those of neurodegenerative origin would facilitate diagnosis and improve patient management. Neurofilaments, which are markers of neuronal lysis, appear to be a promising biomarker. In a previous preliminary study, the investigators demonstrated significantly lower concentrations of neurofilaments in CSF of psychiatric patients compared to neurodegenerative diseases.

The main objective of this study is to validate the plasma assay of neurofilament light chain as a biomarker for the differential diagnosis of psychiatric or neurodegenerative cognitive impairment. Other biomarkers of interest (Tau, TDP-43, GFAP and UCH-L1) will also be analyzed.

A sub-part of this study will also focus on the retrospective analysis of the CSF/Plasma correlations of the different biomarkers mentioned above from tube bottom samples taken in routine care.

One hundred twenty participants will be included in this study

• 30 participants suffering from psychiatric disorders (bipolar disorder or schizophrenia) without cognitive impairment
• 30 participants suffering from psychiatric disorders (bipolar disorder or schizophrenia) with cognitive impairment
• 30 participants with a biological diagnosis of Alzheimer's disease
• 30 participants with frontotemporal dementia according to Rascosky's criteria

All the participants will perform cognitive, behavioral, and psychiatric evaluation and will be have blood sample taken.

Inclusion Criteria:

• haven given written consent

Participants with psychiatric conditions:

• Schizophrenia (DSM-V criteria) with or without cognitive involution
• Bipolar disorder (DSM-V criteria) with or without cognitive involution

Participants with neurodegenerative disease:

• probable or definite FTD (Rascovsky criteria 2011)
• Biological Alzheimer's disease with typical CSF (NIA-AA 2011)

Exclusion Criteria:

• Uninterviewable patient and/or missing history
• History of recent or previous head trauma with loss of consciousness
• History of ischemic or hemorrhagic stroke
• Chronic alcoholism / chronic drug use
• Progressive somatic pathology / severe metabolic disorder / poorly controlled epilepsy
• Age < 45 years
• Age > 80 years
• Electroconvulsive therapy for less than 6 months