Mental illness is extremely difficult to adapt to - much more so than most physical illness except for unremitting pain. So it is terrible for those who experience it. But it is also bad for business, since it gives rise to nearly half of all days off sick. And it is bad for taxpayers, since mental illness accounts for nearly half of all the people who live on disability benefits. Given all this, you would think that mental illness would be high on the priorities of every government's department of health. But not so.