APA Dictionary of Psychology

the overall inherited tendency of an individual to develop a disease or trait, based on the combined effects of multiple genes, including susceptibility genes, and their interaction with environmental and developmental factors. It is often conceptualized as polygenic risk and may involve many variants across the genome. Schizophrenia, for example, is a mental disorder with a genetic predisposition that affects less than 1% of the general population but increasingly larger percentages of distant relatives, siblings, and identical twins of individuals are affected. Also called hereditary predisposition. Compare diathesis.