Immunoinflammatory Mechanisms in Sex-Dependent Vulnerability to Neuropsychiatric Disorders

Sex differences in the innate and adaptive immune systems have long been demonstrated in humans. Genetic, hormonal, and environmentalEnvironmental factors contribute to such differences. Women’s endocrinological transitions, i.e., pubertyPuberty, menopause, and, for some, pregnancy, significantly affect the immune system. Regarding innate immunity, the inflammatory responses in males are increased during infancy, childhood, and old age, whereas females are more likely to develop pro-inflammatory responses in post-pubertyPuberty/adulthood. It is widely known that males are more prone to neurodevelopmental disordersNeurodevelopmental disorder, such as autism spectrum disorderAutism spectrum disorder (ASD), attention-deficit/hyperactivity disorderAttention-deficit/hyperactivity disorder (ADHD), intellectual disability, cerebral palsy, and schizophreniaSchizophrenia. The mechanisms underlying this vulnerability include etiological mechanisms (e.g., genetic factors), which can be influenced by environmentalEnvironmental, cultural, sex-role orientation, biological differences, and hormonal factors. On the contrary, adult females are more vulnerable to mood and anxietyAnxiety disorders, such as major depressive disorderMajor depressive disorder (MDD) and generalized anxiety disorderGeneralized anxiety disorder (GAD), as well as to Alzheimer’s diseaseAlzheimer’s disease. In this chapter, we draw a parallel between the influence of sex on mental illnesses and the possible participation of immune function as a mechanism underlying sex differences. Furthermore, we emphasize the participation of these mechanisms in relevant mental disorders with symptoms onset at different ages, such as autism spectrum disorderAutism spectrum disorder, schizophreniaSchizophrenia, depression, and Alzheimer’s disease.