Hang on, lemme crunch some numbers here.
30% of schizo populace is left-handed.
60% of whole populace is genetically left-handed but only half (30% whole populace) actually do things left handed.
So if 30% of the whole populace is actually lefty in practice, and 30% of schizos are lefty, I think that is a rather expected correlation.
But if you meant genetically lefty people, then you'd expect about 60% of all schizos to be lefties, but if it's only 30%, then actually it sounds like being a righty makes you more likely to go schizo.
Sorry but those numbers kind of said the exact opposite of what Watson claimed. But I guess in a strict sense, yes, lefties are prone to schozophrenia, just like righties and ambidextries and non-...um...dextries are. And just like people are prone to getting shot. Yeah. Sorry, math proves the supposition in the initial post wrong, or I just proved that I didn't learn how to read. One of those. Likely the former, I hope. Either way, Watson's statement here is the same as saying "51% of all humans are women. And guess what, 51% of all depression patients are women!! OH MY GOD BEING A WOMAN MAKES YOU MORE PRONE TO DEPRESSION!!!"