All should listen to James Cameron interviewed by NPR. http://www.npr.org/templates/story/story.php?storyId=123810319

Too much talk here about what and what is not depression. The bigger picture is our ability to become one with our environment. This is not a new concept, in fact it's ancient, but one that has been forgotten and in some cases supressed by those that wish to contol others.
The link above could help people understand that the movie was inspired by what we can be as humans. So the idea is to inspire us to pursue making Earth a Pandora. The beauty of Pandora was inspired by what is real here on earth. The communication between the Na'vi and the environment is also possible by humans. Just a matter of looking within and blocking out the urban clutter we're all bombarded with every day. Read Celestine Prophecy, look into Reiki and various forms of meditation.