Could schizophrenia protect against blindness?
There are several questions I’d want to ask about this study: 1) what are their working definitions of “total blindness” and “schizophrenia”? The latter, in particular, is a much contested term in the hunt for the causes of schizophrenia, where much depends on where you draw the lines that demarcate schizophrenia. This is a perennial problem with the schizophrenia research I’ve read, as well as the secondary literature, and it does make a difference in what you might be looking at. Coming at it from the other angle, they seem to be suggesting that the blindness they’re interested in is congenital, and so they may be limiting their searches to congenital blindness, obviating your reading of the abstract. 2) I’d like to know the rates of mental illness in general in congenitally blind populations. This would be particularly useful because: 3) Schizophrenia presents differently in different cultures. (For instance, there are higher rates of catatonic schizophrenia in many Asian cultures,
I thought I read somewhere that cats were associated anecdotally with schizophrenia. Not knowing how well guide dogs and cats get on in real life, could one hypothesize that blind people own significantly fewer cats (I don’t know if this is true), and that consequently you might find significantly fewer people developing schizophrenia. My point is that the pathway suggested (via brain mechanics) is conjectural. Maybe not as conjectural as my stream of consciousness, but there you go.
That is an absolutely fascinating abstract, srs. Thanks for asking this question. The claims of the article look plausible to me. Lots of work has shown schizophrenics have larger ventricles in their brains, implying extensive cell loss in the brain, and NMDA receptors are excitotoxic, meaning they tend to lead to cell loss; so if blindness does something to inhibit some aspect of the NMDA system, that seems like a good mechanism to explain the very striking observation that “Numerous searches have failed to identify a single co-occurrence of total blindness and schizophrenia.” The question OmieWise raises, of congenital blindness as opposed to blindness later in life, led me to wonder if schizophrenics might be photophobic, but a quick Google search listed first a study which showed a degree of photophilia in schizophrenics! I would really
Here are some interesting clues. Sources available upon request (I have too much work to do than look for it all right now). Smoking might indirectly lead to blindness. Most schizophrenics smoke, but still (according to preliminary research in question) don’t go blind. There is research that smoking helps schizophrenics not be so stupid. Schizophrenic man gouges his own eyes out. Schizophrenics less likely to “fall” for certain optical illusions and typically exhibit lower reactions in N400 ERP experiments.
