Biopsychosocial aspects of depression in different contexts: a view from the inflammatory theory of mental disorders

Abstract

Introduction: Depression is a highly prevalent mental disorder in the population. There is a complexity of this mental disorder that is mainly associated with clinical heterogeneity and the lack of a consistent pathophysiological theory. The multifactorial nature of Depression increases its complexity and it is understood that, in addition to the biological characteristics, it is important to understand the psychosocial factors that encompass this disorder. Both biological predisposition and psychosocial stress can activate the inflammatory response and this appears to be a bridge between the biopsychosocial model of diseases and the inflammatory theory of mental disorders. In recent years, there has been an increase in scientific publications associating an increased inflammatory profile with Depression and other Serious Mental Illnesses (SMI). In addition, the COVID-19 pandemic has brought serious consequences for the mental health of the population around the world. In Brazil, the restrictions imposed by the pandemic also had an impact on the population but there was no data related to psychosocial predictors associated with depressive symptoms. Objectives: The objective of this thesis is to evaluate some biopsychosocial variables associated with Depression in different contexts. This thesis consists of 2 articles. The first article aimed to longitudinally evaluate the association of serum inflammatory cytokines (TNF alpha, Interferon gamma, interleukins 2, 4, 6, 10 and 17) of patients with Major Depression and other GDM (Bipolar Disorder and Schizophrenia) admitted to a psychiatric unit, comparing them with healthy controls and observing the relationship with clinical parameters. The second study aimed to cross-sectionally evaluate the prevalence of depressive symptoms in the initial phase of the COVID-19 quarantine and their association with sociodemographic variables and known protective psychosocial factors for Depression, such as spirituality, social support, resilience and quality of life. Results: Article 1: 206 inpatients were evaluated. 92 patients with Major Depression, 26 with Bipolar Depression, 44 with Mania and 44 with Schizophrenia. IL2 and IL6 levels decreased significantly between admission and discharge only among patients admitted with Major Depression. Overall, patients admitted with GDM had higher cytokine levels when compared to controls, regardless of diagnosis. There was a clinical improvement during hospitalization for all disorders assessed. Article 2: A total of 3274 Brazilian participants completed the online questionnaire in the early phase of the COVID-19 pandemic. 23.67% of participants met the criteria for a depressive episode. Older age, spirituality, social support, resilience, and quality of life were associated with fewer depressive symptoms. Depressive symptoms were higher in women, non-white, single, unpaid, with elementary or high school education, receiving mental health support, not practicing physical exercise, and in the presence of chronic diseases. Length of quarantine, mental health support, presence of chronic disease, age, sex, spirituality, social support, resilience, quality of life and physical exercise, lower levels of education and unpaid occupation were predictors of depressive symptoms during the COVID-19 quarantine. Conclusion: Article 1: There was an increase in serum inflammatory cytokine levels in Depression that is comparable to other GDMs. In depressed patients, clinical improvement is associated with a reduction in IL2 and IL6. Clinical studies involving medications that directly interfere with the inflammatory pathway may be useful for depressed patients. Article 2: There was a high prevalence of Depression during the initial phase of the COVID-19 outbreak in Brazil. The findings can be used to formulate psychosocial interventions to improve mental health during the COVID-19 pandemic.