Environmental Exposures and Neuropsychiatric Disorders: What Role Does the Gut–Immune–Brain Axis Play?

Purpose of Review Evidence is growing that environmental exposures—including xenobiotics as well as microbes—play a role in the pathogenesis of many neuropsychiatric disorders. Underlying mechanisms are likely to be complex, involving the developmentally sensitive interplay of genetic/epigenetic, detoxification, and immune factors. Here, we review evidence supporting a role for environmental factors and disrupted gut–immune–brain axis function in some neuropsychiatric conditions. Recent Findings Studies suggesting the involvement of an altered microbiome in triggering CNS-directed autoimmunity and neuropsychiatric disturbances are presented as an intriguing example of the varied mechanisms by which environmentally induced gut–immune–brain axis dysfunction may contribute to adverse brain outcomes. Summary The gut–immune–brain axis is a burgeoning frontier for investigation of neuropsychiatric illness. Future translational research to define individual responses to exogenous exposures in terms of microbiome-dependent skew of the metabolome, immunity, and brain function may serve as a lens for illumination of pathways involved in the development of CNS disease and fuel discovery of novel interventions.