How can you be depressed?.... you seem so happy....

The heartbreaking news of the death of Stephen "Twitch" Boss shook the world as it was hard to come to terms with someone who appeared so happy could have been suffering from depression. In the behavior/mental health community we have some insight to this though. Have you heard of smiling depression? The happiest of people can struggle with depression yet still smile. So what is it? Let's talk about some basics.