I think it's like being an alcoholic - if you have it, you always have it, even if it is controlled or in remission.
I had a catastrophic breakdown twenty-three years ago, was hospitalised for three months, off work for a year, and am on anti-depressants, probably for life.
I absolultey know the difference between Depresson and 'being depressed' as I outlined n the other thread.
The major difference for sufferers like me is that the normal instances of 'being depressed' hold a cold cold fear that they are not the start of the return of something far worse.