I definitely experience that slowdown, although I didn't actually notice it in myself until my counselor pointed it out to me. But yes, I do move very slowly when I'm depressed, mostly because even the smallest motion seems to require a huge amount of effort. I also hate making noise of any kind -- heavy footsteps, setting things down and having them bang together, slammed doors, etc. I have almost always been this way, as loud noises -- even when I'm the one causing them -- put me on edge. I'm not entirely sure if it's depression related or if it's something else. Definitely gives me something to think about though.