Some experts argue that depression can be a positive life-changing experience that leaves people tougher, more resilient and more creative.
Some even argue that depression may not be an illness at all, but an evolutionary survival mechanism that helps us cope with life's crises by forcing us to reassess our priorities.
Eleven years ago, Helen McNallen suffered an episode of depression so severe she attempted to take her own life.
She set it up because she is convinced that her mental health crisis, which was triggered by the pressures of her job, has, in the long run, transformed her life for the better.
"I'm glad I had depression," says Helen, from Sheffield in South Yorkshire.
"Now, I feel very lucky to be able to spend my time helping other people. It was a turning point in my life," she added.
The controversial idea, that depression might do some of us good in the long run, is backed up by a recent study carried out in the Netherlands.
It analysed the effects of depression on 165 people by looking at how well they coped with life's stresses and strains before and after their mental breakdown.
The study found that the majority had more vitality, improved social lives and were performing better at work.
But if suffering mental health problems really can be beneficial, experts agree it's only likely to apply to those with mild to moderate depression - the majority of cases.