[dkersten]

Yep. In my experience, external factors such as smiling, laughing, joking and being active are completely disconnected from and have no bearing on someones internal emotional state when depressed.

That is, in my personal experience and in my experience knowing others who have suffered from depression, you can feel completely down and hopeless and emotionally distraught without this being visible to those around you, who simply see you being active, acting happy, smiling, joking and so on. These things do not mean that you aren't depressed. The thing that makes depression what it is, is the feeling of hopelessness and/or emptiness even when these other things are present and even when there's seemingly no reason for it.

Many depressed people get very good at bottling up and hiding their emotions.