This article is a short excerpt from this paper (in review): A call for the inclusion of religious schizophrenic disorder (RSD) in the DSM It is well known to psychological science, genetic psychiatry, and behaviour genetics that certain people have genetically based vulnerabilities to certain kinds of mental disorders and personality disorders. One can use the following simple equation to express the contributions of nature (G or genetics) versus nurture (E or environment) to the formation of a particular trait or phenotype (P): P = G + E (1) The distinction between nature and nurture is often not helpful and can be blurred depending upon which disorder and which diagnostic criteria are of interest (Barlow, 2019; Crews et al., 2014; Schwartz, 1998) . However, there are few cases – and the number of cases is diminishing as more data and superior experimental designs and techniques become available – where genetics is not a known, significant aetiological factor. Nonetheless, t...