In my experience, mental health issues are epidemic. The only question is if someone has been assessed, and then had a professional admit to them they have a diagnosis. Mind you, it's hard to be healthy, and most people are still functional (as much as our late-state capitalist society will let them) but we noticed that mental illness was epidemic in the 1990s, likely due to major societal shifts in the industrial age: We're used to having more of a social support system than we do. So I suspect that we're all mad as hatters, and it's intergenerational.