Neurological and Neurochemical Aspects of Anxiety Disorder: An Integrative Literature Review

Abstract

Anxiety disorders currently constitute one of the major mental health problems worldwide, presenting high prevalence and significant impact on individuals’ quality of life, social functioning, and physical health. In this context, recent studies have demonstrated that anxiety is not restricted to emotional or behavioral manifestations, but also involves complex alterations in brain circuits, neurotransmitters, neuroendocrine mechanisms, as well as genetic and epigenetic processes. This study aimed to identify and analyze recent scientific evidence on neurological, neurofunctional, and neurochemical alterations associated with anxiety disorders, with emphasis on synthesizing current knowledge and identifying gaps for future investigations. This is an integrative literature review, organized according to the PICO model and guided by an adapted PRISMA 2020 flowchart, supported by PRISMA-S logic. Searches were conducted in the SciELO, LILACS/BVS, and PubMed/MEDLINE databases, considering publications between 2020 and 2025, including primary studies and secondary syntheses related to neuroimaging, functional connectivity, neurotransmitters, biomarkers, genetics, epigenetics, and neuromodulation. A total of 71 records were identified, of which 5 composed the final corpus, including 2 primary studies and 3 secondary syntheses. The findings focused on panic disorder, indicating activation of the amygdala and inferior frontal gyrus, alterations in insular connectivity, and the involvement of GABA, serotonin, glutamate, orexin, the HPA axis, BDNF, IL-6, leptin, lactate, and genetic or epigenetic factors. It is concluded that anxiety disorders require an integrated understanding of the brain, body, and molecular regulation, with no single biomarker available for diagnosis or treatment, highlighting the need for primary research with larger samples and multimodal protocols.