It’s classified as a personality disorder in the DSM. Schizotypy is a combination of traits that psychologists have discovered often go together. But Del Giudice, building on work by Badcock and Crespi presents the “diametrical model”: schizophrenia and autism are the failure modes of opposing sides of a spectrum from high functioning schizotypy to high functioning autism, ie from overly mentalistic cognition to overly mechanistic cognition. I’ve previously been skeptical of this kind of thinking because there are many things that autists and schizophrenics have in common, many autistics who seem a bit schizophrenic, many schizophrenics who seem a bit autistic, and many risk factors shared by both conditions. Autists can be pathologically rational but tend to be uncreative schizophrenics can be pathologically creative but tend to be irrational. Schizophrenics are more susceptible to the rubber hand illusion and have weaker self-other boundaries in general autists seem less susceptible and have stronger self-other boundaries.

Schizophrenics smoke so often that some researchers believe they have some kind of nicotine deficiency autists have unusually low smoking rates. Autists have a smaller-than-normal corpus callosum schizophrenics have a larger-than-normal one. Many of the genes that increase risk of autism decrease risk of schizophrenia, and vice versa. There’s been a lot of discussion over whether schizophrenia is somehow the “opposite” of autism.

One interesting thing I took from Evolutionary Psychopathology was a better understanding of the diametrical theory of the social brain.

Star wars autistic screeching