Estudo da associação entre desempenho cognitivo, qualidade de vida e marcadores inflamatórios em pacientes com esquizofrenia ou transtorno delirante

Abstract

Introduction: Cognitive impairment is a nuclear finding in schizophrenia. This disorder is also characterized by low quality of life. Delusional disorder is a similar, but less serious mental condition. Recent evidence has implicated immune and inflammatory changes to cognitive performance in many diseases, including schizophrenia. Objectives: The objective of the present study was to analyze correlations between serum cytokine levels, cognitive performance and quality of life in a sample of stable, medicated, schizophrenic outpatients in Brazil. Methods: 63 outpatients diagnosed with schizophrenia or delusional disorder were evaluated with a cognitive battery (BACS), coprimary measure (SCoRS) and quality of life scale (QLS-BR). Blood samples were taken and serum levels of IL-2, IL-4, IL-6, IL-10, IL-17A, IFN- and TNF were measured by cytometric beads array. Selection and control of variables was assessed through other scales (MINI-Plus, PANSS, ECDE, AIMS, and SAS), medication and demographic status. Statistic analysis: Spearman correlation test. A dimensional reduction factor for BACS was created, to account for its total score. Results: IL-6 levels were inversely correlated to phonetic verbal fluency, motor speed and cognition total score (BACS reduction factor), with significant p values: 0,042, 0,047 and 0,044 (respectively) and rho: -0,322, -0,315 and -0,320. IL-4 was positively correlated to quality of life (QLS-BR), with p=0,013 and rho=0,361; and inversely correlated to depressive symptoms (ECDE). TNF was inversely correlated to age and IL-6 was also correlated positively to chlorpromazine equivalents (in miligrams). Conclusions: Cognitive impairment in schizophrenia may be partially mediated by proinflammatory cytokines, which also appear to be associated to higher doses of antipsychotic medication. Immunomodulatory cytokines may be associated with quality of life and mood in the disease. Further research is needed to clarify the topic and the possible associations between cognition, quality of life and immune system in schizophrenia.