Neuroinflammation and the Female Brain: Sex-Specific Mechanisms Underlying Mood Disorders and Stress Vulnerability

Women exhibit a higher prevalence of depression, anxiety, stress-related disorders, and autoimmune conditions compared to men, yet the biological mechanisms underlying this sex difference remain incompletely understood. Growing evidence identifies neuroinflammation as a central mediator of psychiatric vulnerability in women, shaped by interactions between sex hormones, immune activation, and neural circuit regulation. Throughout the female lifespan, fluctuations in estrogen and progesterone, such as those occurring during puberty, the menstrual cycle, pregnancy, postpartum, and perimenopause, modulate microglial activity, cytokine release, and neuroimmune signaling. These hormonal transitions create windows of heightened sensitivity in key brain regions involved in affect regulation, including the amygdala, hippocampus, and prefrontal cortex. Parallel variations in systemic inflammation, mitochondrial function, and hypothalamic-pituitary-adrenal (HPA) axis responsivity amplify stress reactivity and autonomic imbalance, contributing to increased risk for mood and anxiety disorders in women. Emerging data also highlight sex-specific interactions between the immune system and monoaminergic neurotransmission, gut-brain pathways, endothelial function, and neuroplasticity. This review synthesizes current neuroscientific evidence on the sex-dependent neuroinflammatory mechanisms that bridge hormonal dynamics, brain function, and psychiatric outcomes in women. We identify critical periods of vulnerability, summarize converging molecular pathways, and discuss novel therapeutic targets including anti-inflammatory strategies, estrogen-modulating treatments, lifestyle interventions, and biomarkers for personalized psychiatry. Understanding neuroinflammation as a sex-specific process offers a transformative perspective for improving diagnosis, prevention, and treatment of psychiatric disorders in women.