I haven't had a true, severe depression in a while, but when I'm there, multiple things happen.

1. I feel sluggish as molasses. I feel like every particle in my body is slowed down and I can't move any faster than about one-quarter speed.
2. I don't talk unless it's strictly necessary. Like I'll say one-word responses and only talk if someone addresses me directly. Otherwise I don't bother.
3. I feel sad. The weight of the world is upon me and there's nothing I can do to solve every problem out there.
4. I don't initiate anything with friends or family: I just sit in my room, sometimes listening to music (usually of the sad variety) or staring at the wall.
5. I can't get up in the morning even if there were a giant foghorn, someone yanking me out of bed, or a million little dwarves trying to wake me up and reminding me what beauty there is in the world.
6. My neural circuits don't work. I can't recall basic facts or information, or sometimes just don't want to, if addressed by others.
7. I can't concentrate for a good period of time on nearly anything.
8. There's nothing anyone can possibly do to rouse me from my state.


Okay, that's enough description of it. But hopefully it makes some sense what I said.