The inability to hold down a job is a very common symptom of mental illness. In other words, it is no secret that your mental health hinges on whether or not you contribute to the economy.
Well I do fully believe that for most people their sense of self worth hinges on having responsibilities and a regular schedule, but that can mean being a mother, volunteering on a regular basis, being a part of your retirement community's bingo club, or whatever else.
But what is also true is that losing your job can be a precipitous plunge into mental illness, as your outside world that was regularly structured turns to chaos suddenly. And of course, if your external world becomes chaotic, your internal world is liable to be chaotic as well--'as above, so below' and all that.
I think you may have causality backwards there. Its more likely that people with mental health issues have problems functioning in the usual work environment, they don't mesh and have trouble keeping the job because of it.
