What is the difference between passive-aggressive behavior and depression behavior? People sometimes mislabel depression behavior with passive-aggressiveness. How do we stop that?

I'm not sure the two are mutually exclusive. A person suffering from depression may express themselves in passive-aggressive ways, but it does not belittle their depression or make it less serious; similarly a person who is typically passive-aggressive might become depressed; of course, there may be no link between the two. It is extremely individual and each person may experience depression differently and express it in different ways. There is however a lot of social stigma about depression, which was a very important point that you bring up. Ultimately we have no control over what other people think or say, but we can control what we do about it; it's possible that through honest communication and repetitive communication, we can start to change the world so that people who experience depression in the next generation won't have to deal with as much stigma as we deal with today. Strength in numbers and honesty! Great questions!