It's not depression or bipolarity, probably, but for the purposes of this discussion the difference is probably irrelevant.

I never claimed the 50% thing was ever anything other than a gross simplification to make the math easier. Obviously it's much more complicated than that with other factors, less extreme numbers, and so on, but the end result is still isomorphic to it. Maybe it's even polynomial rather than exponential, but it's still a huge problem.