"It is probable that it's double that." Wow, that would mean 40% of the general population. That is a very high percentage.
Why do you think that's high? AMA predicts by 2020 that depression will the third leading cause of death. We die because of failure or trauma and everything is really a sympton (Heart/Stroke, Cancer, etc) What the AMA is saying that the way the world is and the aging population depression increases. 20% are diagnosed because they seek help or fall into a system of sorts that results in a diagnosis. How many people don't have access to health care, clinicians, medication and other supports? Ok, you can't afford help, that will probably cause more depression and take the person further into an abyss.
Do you really know the people that you work with or your neighbours? Do you really know what's happening behind closed doors and outside of the office, and do you care? When do we care, when something traumatic happens and that's only a reactive response. Think of the extensions of people in someone's life that become affected due to depression or illness.
Clara Hughes suffered for two years, she's lucky and she's advocating for others. It's really a deep subject. I'm sure that many will now post people are weak, etc, and it's not worth getting into a heated debate.