yes for me I feel other people's depression when I see them that their life make so much sin. I feel pity on them at the same time I feel the depression of their life. I dont know that people can feel other people's sad life.
Depression is actually a state of mind. So it could be considered as an illusion. So is the happiness is also an illusion of our own mind. So if you could change your state of mind through different things such as deep relaxation meditation and other mental excercises you can beat depression. That's the same thing the doctors are doing through anti-depressant medication changing the state of mind through drugs......
:sorry I hv no idea.beings with even subtle bodies will be made of 5 elements much like humans.dark matter is included in all.Dark matter is the space which is not physical.