Do you have a source for that? I couldn't find any mention of that in the Wikipedia article (https://en.wikipedia.org/wiki/Fluoxetine#History), and it seems, from the history I've tracked down, like SSRIs were specifically developed with an intent to treat mood disorders.

There does seem to be a combination drug that includes prozac and olanzapine that's used to treat psychotic disorders. It's been on the market for a while; maybe that's resulted in some confusion?