I have banged on about this many times - but will happily do so again.
The problem is the word 'depression', which in many people's minds, means 'depressed' which is not the same thing at all.
Being depressed is part of the human condition. We all have it, occasional days when we feel down and a bit fed up, but it's transitory, and it does not last, and it balances our emotions for us.
Deprression is a debilitating and often fatal mental illness. Sufferers may have recurring bouts with varying severity throughout their lives. With increasingly sophisticated modern anti-depressants, a lot of peoples' symptoms can be controlled with regular medication, which may be for life, and as has been advised, it is control, rather than cure, much like insulin for a diabetic.
To confuse 'being depressed' with 'depression' is to confuse a sprained ankle with a foot amputation with a rusty tin lid and no anaesthetic - the gulf really is that wide!
I for one would prefer a different noun for the condition - preferable one which has the same instantant chilling ring as 'cancer' - no room for misunderstanding there!
So, you can be as rich as Cresus and still be depressed, and have depression - the two are not lined, except by a similar descriptive noun.
Making people aware of the difference between the two helps sufferers to avoid the 'What ahve you got to be depressed about?' line which really does not help!