When you are depressed you draw into your self. think of a flower that once was open but due to life, circumstances , how one perceives ones self, if they are craving attention good or bad and consequences to how they behaved from normally busy family and friends, negative( to them) feed back on the way they look to the way they talk or act... they slowly start to close themselves off from anything to do with the real world; like a flower closing back up on itself. the fantasy world is where you run to to find yourself again because depression zaps who you are/ were. depression is the worst form of you. Its the stage or few stages before one tries to kill themselves. It is where your asking for help on the inside and praying someone Anyone will notice because you verbally cant ask for help. All the while belittling yourself for not being able to get yourself out while mad at the world for not seeing the pain and angish your keeping from them so someone ANYONE can help you.
This is the best way I can describe depression. It sounds like a good idea and it would help teens come to grips with this topic. Hope this helps and Good luck.