since many of you almost feel like family, I would like to get this out there. I heard last night that a good old friend of mine in Germany commited suicide after experiencing depression. While we all have busy lives, I would just like to encourage you to keep your ears and eyes open for friends who may be struggling with depression. Almost 10% in the population are affected by some form of it, almost 4% are affected by Major Depression. Chances are good that you know someone who is affected. This is not a temporary mood problem or a weakness. Major Depression is a severe condition that can and in most cases does affect peoples' lives - their job performance, family life, relationsips, social life etc. 10% of Major Depression patients commit suicide, even more may attempt it. Sometimes it is easier to see some of the signs from the outside than when you are affected yourself. Please have a look at what the main symptoms are and at what you can do. A few ideas are in the second link. The main thing is to provide support without nagging, and not to drop your support when you don't get the reaction you hope for. For example, keep inviting people, even if they haven't shown up the last 5 times - not being able to incolve oneself in social events is part of the disease, but seeing that people don't give up on you can make a huge difference for people who struggle.
It is really unfortunate that there still seems to be some stigma attached to mental health issues, including depression. There is a lot of work to do in educating each other.