This post is dedicated to Robin Williams . . . may he rest in peace
According to Wikipedia, "depression is a mental disorder characterized by a pervasive and persistent low mood that is accompanied by low self-esteem and by a loss of interest or pleasure in normally enjoyable activities. Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair, the cause of which is frequently attributed to a mental disorder such as depression."
In my opinion, depression is not understood by society in general. Many have the opinion that depression is just an imagined ploy to get attention. They see it as "victim mentality." Too bad everyone is not perfect as they are. (I am being sarcastic, but exactly how I feel about these type of people.)
"Get over it" they will tell the depressed person, making that dark tunnel darker, the light at the end of that tunnel fainter. The depressed person is left feeling like a freak of nature.
You just don't "get over" depression! Those who don't care enough to understand the depression of a loved one should be ashamed of themselves! Depression is real and is painful, especially when the support of loved ones is not there.
Many who are depressed will probably not admit to being depressed due to the stigma associated with it, making it a very dangerous situation. There are tools to deal with depression, but without seeking professional help, a dangerous situation can become worse.
At best they will live a relatively sad life.
When they can't "get over" the depression, the decision is made by that person whose pain is so awful that they can't take it another day, with that dark tunnel in total darkness . . . that person will be left with the feeling they have no other option in life but to end it.