Blindness, Schizophrenia, and Autism
Some weird psychiatric trivia: no congenitally blind person ever gets schizophrenia (journal article, popular article). “Trivia” is exactly the right word for this fact; it’s undeniably interesting, but what do you do with it? So far nobody has done anything, other than remark “hmm, that’s funny”.
I was thinking about this recently in the context of the diametrical model of autism vs. schizophrenia. This is itself pretty close to psychiatric trivia - a lot of features of schizophrenia and autism seem to be opposites of each other. As I put it here:
Many of the genes that increase risk of autism decrease risk of schizophrenia, and vice versa. Autists have a smaller-than-normal corpus callosum; schizophrenics have a larger-than-normal one. Schizophrenics smoke so often that some researchers believe they have some kind of nicotine deficiency; autists have unusually low smoking rates. 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. Autists can be pathologically rational but tend to be uncreative; schizophrenics can be pathologically creative but tend to be irrational. The list goes on.
In theory you could use this kind of thing to help figure out what causes both conditions. In practice, it’s a lot more complicated. Autism and schizophrenia also resemble each other in a lot of ways, a lot of the genes for one also increase risk for the other, and some people even get diagnosed with both. I try to make sense of this conflicting information by speculating that autism has at least two components, which are correlated and anticorrelated with schizophrenia respectively (see here for guesses about what these might be), but still - all speculation and trivia.
