Biomarkers as proxies for cognitive reserve: The role of high density lipoprotein cholesterol in first episode of psychosis

Abstract

Introduction

The proxies used to compose cognitive reserve (CR) for patients of a first episode of psychosis (FEP) have varied in the literature. The development of FEP is linked to peripheral pathways of the central nervous system, yet despite this knowledge, no research has considered the introduction of biomarkers as proxies for CR. Meanwhile, schizophrenia has been linked to the metabolic system, indicating that alterations in the levels of biological parameters, in particular high-density lipoproteins (HDL), cause worse global functioning and cognitive impairment. For these reasons, the present study aimed to create a quantifiable and objective CR index that adjusts for the multifactorial nature of FEP.

Materials and methods

We included 668 FEP patients and 217 healthy controls. Participants were assessed for sociodemographic information, years of education, employment status, premorbid IQ and biological parameters: waist circumference, hypertension, and levels of HDL, triglycerides, and glucose.

Results

The findings suggest that the years of education proxy showed correlational and higher relationship with HDL levels for both FEP patients (r = 0.23, b = 0.185) and controls (r = 0.31, b = 0.342). We found that the CR index composed of years of education and HDL levels showed a higher explanatory power for the phenomenon than the classical CR index composed of years of education, employment status and premorbid IQ.

Conclusions

This article proposes an objective and quantifiable method to measure CR that is more the multifactorial nature of FEP.