I'll have to read the article to really understand what the authors have found out, but judging from the summary the advance is dividing the huge number of gene

I'll have to read the article to really understand what the authors have found out, but judging from the summary the advance is dividing the huge number of genes linked to schizophrenia into 8 groups of genes that associate or interact more closely than with other related genes. In many ways, this isn't surprising. It's been evident that many genes have been linked to psychiatric disorders, but no "smoking guns" are evident, usually a gene accounts for <2% of the variance, and dozens or hundreds of genes have some influence. So it's logical that it takes a cluster of many genes contributing something to have enough effect to be clinically apparent. How genes interact is an enormously complicated matter, and perhaps an even bigger question is the role of gene-environment interaction. One thing to track is with the multitude of genes shown to be clustering, an important element is how "tight" the clustering is. I anticipate we'll find out as it's investigated further that overlap among clusters is significant, that is, "blends" or mixed/intermediate types are probably common. Certainly in the real world there are seldom pure cases of any condition, the boundaries tend to be fuzzy. Not that the article implies at all that the new work gives "answers", but with any luck, it will lead to new insights, shed light on the astonishingly complex processes, and clues to making progress. Just expect the path will have many more twist and turns on the way there.