Inflammatory Mechanisms in Anxiety Disorders

Anxiety disorders are increasingly recognised as conditions not only of altered neural circuitry but also of immune dysregulation. Chronic stress and hypothalamic–pituitary–adrenal (HPA) axis activation can promote low-grade systemic inflammation, characterised by elevated proinflammatory cytokines such as interleukin-6, tumour-necrosis-factor-α and C-reactive protein. These circulating mediators may access the brain via disrupted blood–brain barrier permeability or active transport mechanisms, triggering microglial activation and neuroinflammation within limbic and prefrontal regions. Such immune-to-brain signalling can alter synaptic plasticity, neurotransmitter metabolism and neural network connectivity, thereby exacerbating anxiety symptoms. Conversely, anxiety phenotypes may further amplify inflammatory responses through autonomic imbalance and behavioural pathways, creating a feed-forward loop. Identification of specific cytokine profiles and immune cell signatures has opened new avenues for diagnostic biomarkers and adjunctive therapies. Anti-inflammatory agents, cytokine antagonists and lifestyle interventions aimed at reducing systemic inflammation show promise in modulating anxiety severity. Understanding these bidirectional interactions holds global significance for preventive strategies, personalised treatment and the development of novel immunomodulatory approaches in mental health care.

Research from Nature Portfolio

Recent studies have reported elevated serum levels of interleukin-17A and interleukin-23A in individuals with generalized anxiety disorder compared with healthy controls. The magnitude of these cytokine changes correlated positively with symptom severity, suggesting a role in both pathophysiology and risk assessment. Receiver-operating characteristic analyses indicated that these interleukins may discriminate patients from controls with moderate sensitivity. These findings highlight Th17-related pathways as potential therapeutic targets and call for longitudinal studies to validate their utility as early biomarkers.

Inflammatory Mechanisms in Anxiety Disorders publication trend

The graph below shows the total number of articles in inflammatory mechanisms in anxiety disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Cytokines: small signalling proteins that coordinate immune responses and modulate inflammation.

Interleukin-17A (IL-17A): proinflammatory cytokine produced by T helper 17 cells implicated in tissue inflammation.

Blood–brain barrier (BBB): selective endothelial interface regulating entry of blood-borne substances into the central nervous system.

Neuroinflammation: activation of immune pathways within the brain, involving microglia and astrocytes.

Mendelian randomisation: genetic epidemiology method using inherited variants to infer causal effects between exposures and outcomes.

References

1. Causal role of immune cells in generalized anxiety disorder: Mendelian randomization study. Frontiers in Immunology (2024).
2. Altered serum interleukin-17A and interleukin-23A levels may be associated with the pathophysiology and development of generalized anxiety disorder. Scientific Reports (2024).
3. Systematic review and meta-analysis of the association between peripheral inflammatory cytokines and generalised anxiety disorder. BMJ Open (2019).