“As psychologist John Read has shown, there are 15 ways that two people can meet the DSM criteria for schizophrenia without sharing any symptoms in common.”
This article by Dr. Jay Joseph has been published by Mad in America. It begins:
“In a 2003 edition of Science, the editors declared that the identification of genes for ‘mental illness’ was the second most important ‘scientific breakthrough’ of the year. ‘Schizophrenia, depression, and bipolar disorder often run in families,’ the editors wrote, ‘but only recently have researchers identified particular genes that reliably increase one’s risk of disease.’ The prefrontal cortex, they wrote, ‘is regulated in part by a gene called COMT, one of the handful associated with risk of schizophrenia.’
As it turned out, claims based on these ‘particular genes’ didn’t hold up, including the COMT gene. When a journal as prestigious as Science says that genes for psychiatric conditions have been discovered, most people take this as fact—and remember it as fact. But in this case, it turned out not to be a fact. Despite the development of new techniques leading to current claims of gene associations based on genome-wide association (GWAS, based on common single nucleotide polymorphisms, or SNPs), polygenic risk score (PRS), and copy number variant (CNV) studies, genes shown to cause ‘schizophrenia’—a questionable concept in and of itself—remain undiscovered …”
You can read more from here.