If genes that increase schizophrenic risk increases cognitive abilities you should find people who have high polygenic scores for schizophrenia without having schizophrenia test well on these cognitive abilities. I'm not aware of any of data that shows this in a convincing matter. I think I've seen a few small studies but nothing that replicated this on a large scale. And most of the studies show they score worse on cognitive abilities.
The only conclusions I've come to are one of the following.
1. They improve cognitive abilities in some way we aren't good at measuring. 2. There is something about our modern environment that is more likely to trigger schizophrenia which has more recently increased the fitness penalty these genes confer.
replies(2):