INTRODUCTION: The understanding of the pathophysiology of bipolar disorder has steadily advanced in the past few years. Thereby, a focus on allostatic load and systemic changes has appeared, with the aim to understand illness progression. Amongst the peripheral markers, molecules that can be widely classified into neurotrophins, oxidadive stress markers, and inflammation markers have been elevated. OBJECTIVE: To describe recent findings regarding the systemic pathophysiology of bipolar disorder, with a special focus on Brazilian studies and to create a coherent view of the current knowledge in the field. METHOD: Narrative review of the literature regarding neurotrophins, oxidative stress, and inflammatory markers in bipolar disorder. RESULTS: A diverse body of evidence, based on both pre-clinical and clinical studies, reveals consistent systemic changes in bipolar disorder. The findings are particularly robust in patients after multiple episodes. Thereby, remarkable changes related to manic and depressive episodes were found in neurotrophins and oxidative damage to lipids. Regarding to immune system alterations, in particular pro-inflammatory states, the literature is less consistent. DISCUSSION: Systemic changes that link bipolar disorder to clinical comorbidity, cognitive dysfunction, disability and early mortality are becoming evident. In the near future, longitudinal studies with population-based samples and clinical trials incorporating biomarkers are needed to shed light upon the notion of a multisystem involvement in bipolar disorder.
Bipolar disorder; inflammation; oxidative stress; neurotrophins; brain-derived neurotrophic factor; pathophysiology; biomarkers
