The role of prenatal immune activation in the pathogenesis of autism and schizophrenia: A literature review

Autism spectrum disorder (ASD) and schizophrenia (SZ) are two neurodevelopmental disorders that, despite having distinct diagnostic criteria, share certain clinical and etiological features. The genetic origin of the two disorders is beyond doubt, with evidence for unique and overlapping genetic risk factors. However, lower estimates of heritability have recently been reported for both disorders, lending support to a significant contribution from non-genetic factors. Notably, there is increasing evidence that immune activation during prenatal life may act as a risk factor for ASD and SZ. In this review, evidence supporting the hypothesis that prenatal immune activation (PIA) influences the onset and progression of ASD and SZ is analyzed. Results show that the detrimental effects of PIA on neurodevelopment include morphological changes in various brain regions, with perhaps the most notable being the hippocampus and prefrontal cortex, as well as altered activity of neurotransmitter systems such as the serotonergic system and impairments in working memory and prepulse inhibition. An examination of the risk factor of PIA offers new insight into the pathophysiology of ASD and SZ, and in this way opens up new possibilities for the treatment of these two disorders.