Imprinted brain hypothesis

The imprinted brain hypothesis is a hypothesis in evolutionary psychology regarding the causes of autism spectrum and schizophrenia spectrum disorders, first presented by Bernard Crespi and Christopher Badcock in 2008. It hypothesizes that genomic imprinting effects contribute, to some degree, to the diametric (opposite) nature of autism and psychosis (the diametric disorders hypothesis, which is much more general than the imprinted brain idea). The imprinted brain hypothesis is based around genomic imprinting, an epigenetic process through which genes are expressed differently depending upon which parent they are inherited from. Specifically, the imprinted brain hypothesis proposes that autism spectrum disorders are caused to some degree by biases towards paternal gene expression, while psychosis spectrum disorders are caused in some cases by biases towards maternal gene expression. The imprinted brain hypothesis is supported by high rates of autism in Angelman syndrome (which is due to paternal imprinted gene biases) and high rates of psychosis in Prader-Willi-syndrome (which is due to maternal imprinted gene biases). The diametric disorders hypothesis and the imprinted brain hypothesis have been subject to considerable research and testing, with considerable support and some non-supportive evidence, e.g., .