We’ve been gradually working our way through the conversation around E. Fuller Torrey’s concerns about schizophrenia genetics - last week we had It’s Fair To Describe Schizophrenia As Probably Mostly Genetic, the week before Unintuitive Properties Of Polygenic Disorders. Here are two more arguments Torrey makes that we haven’t gotten to:

1. Studies have failed to find any schizophrenia genes of large effect. If schizophrenia is genetic, it must be caused of thousands of genes, hidden in the most obscure corners of the genome, each with effects too small to detect with current technology. This seems less like the sort of thing that happens naturally, and more like the sort of thing you would claim if you wanted to make your theory untestable.
2. Schizophrenia is bad for fitness, so if it were genetic, evolution would have eliminated those genes.

In the comments of the Unintuitive Properties post, Michael Roe points out that one of these mysteries solves the other:

https://www.astralcodexten.com/p/evolution-explains-polygenic-structure