Peripheral biochemical correlates of social anxiety disorder: a systematic review focused on inflammatory markers, neuropeptides, hormones, and gut microbiota

OBJECTIVE: Social anxiety disorder (SAD) is common debilitating condition marked by intense fear of negative evaluation in social situations. It frequently co-occurs with other psychiatric disorders and substantially impairs quality of life. Although its aetiology remains unclear, like many other complex psychiatric disorders, SAD is thought to arise from interactions among biological and environmental factors. Increasing attention has been given to the role of neuropeptides, neurohormones, and immune system processes, particularly inflammation, in its pathophysiology. This review aims to evaluate and synthesise scientific evidence on the potential biochemical correlates of SAD in clinical populations, concentrating on inflammatory markers, neuropeptides, and growth factors. METHODS: Electronic databases (PubMed, Scopus, and Web of Science) were searched according to PRISMA guidelines, resulting in 27 studies included in the final analysis. RESULTS: The research into biochemical correlates of SAD has yielded promising but inconclusive results, particularly regarding inflammation, microbiome changes, and immune system interactions. Overall, the evidence supports the hypothesis that the inflammatory cascade plays a role in the persistence of the disorder. CONCLUSIONS: Although some markers show promise in advancing our understanding of SAD's pathophysiology, further research is necessary to clarify their roles and validate their potential in diagnostics and treatment.