I have always hated the term Depression for my illness - because when you say it, people think you are depressed, which is absolutely not the same thing.
As I have said many times, being depressed is part of the human condition - everyone has periods where they feel low, and those periods are usually short and pass without any real difficulty.
Depression is something very different indeed.
To me the comparison is - if being depressed is having a sprained ankle, then Depression is having your foot cut off with a rusty tin lid - that's how big the gulf is between the two.
I do agree with other posters, there is more openness about mental illness these days, it is slowly losing the dreadful stigma it attracted until reasonably recently.
You were said to be 'suffering with your nerves' which didn't really say anything, and anyone confined to a psych ward was usually not mentioned, except in hushed tones.
Most psych hospitals dated from Victorian times and were usually large places with high walls, avoided by the locals.
In fact, the Victorians had absolutely the right idea - an asylum is a place of safety, and these large hospitals with their massive grounds and walls meant that patients could roam about in the peace and quiet and not venture onto roads and get lost or run over.
I was in one for three months, and it kept me safe - I would have been utterly unable to cope with traffic, and would probably have availed myself of the chance to jump under a lorry. I roamed the grounds all day every day, and gradually got my mind back.
I would wish that the word 'depression' had the same ring of fear and seriousness as 'cancer' - maybe in time the term will evolve.