Have you ever paid attention to the ages of employees in almost any retail store? Where are all the 50 year-old plus people? With one exception, they just aren't there. The exception, of course, is WalMart. But that's a topic for another time.
Where are the middle aged people with mental illness? You don't hear about them like you do young people - it seems like it's always young people we read about after a mania landed them in the hospital or in custody. I would suspect society has flushed out middle aged sufferers. They learn how to hold a job and quietly fit into society. Or they're institutionalized - I recently read about an explosion of people with mental illness residing in nursing homes with elderly residents. Or they're homeless, or in jail, or dead.
Depending on the study you want to believe, up to 25% of those with bipolar disorder will suicide. I assumed the majority of those were student age, up to young adult. I just read an article that amazed me - the largest number of suicides among people suffering from a mood or other mental disorder is middle aged women.
Suicide spikes among middle-aged women
Amazing, but sad.