Depressed? Or down in the dumps?

Where's the line between being depressed and just being down in the dumps?

There's been a 40% rise in the use of anti-depressants in England. Doctors wrote 23 million prescriptions for them last year.

Professor Gordon Parker from the Black Dog Institute in Sydney tells us that too many people say (or are told) that they're depressed when actually they're just unhappy.

Nicky Campbell is also joined by Mark Davies from the charity Rethink Mental Illness.