I went out on my first family practice visit this week. This is part of a course wherein we work with a preceptor at his family practice and get some hands on experience doing patient interviews and taking vital sign readings.
During this visit, I learned that patients can develop tremors that come on due to anxiety. When I saw the tremors, I immediately thought Parkinson's (mostly because it was the only cause of tremors I had known about at the time); however, these tremors were physically different than Parkinson's tremors. Instead of the trademark wrist grind of Parkinson's, anxiety tremors are a constant shaking. Also, anxiety tremors do not go away when the afflicted individual attempts to do something this his hands, whereas in Parkinson's the tremors often go away when the individual uses their hand (e.g. reaching for a glass).
Anyhow, these anxiety tremors, often caused by depression, are brought on solely by anxiety. The emotional stress induced by constant anxiety causes the brain to lose control over the body's nervous system and causes neurons in the arms to fire, causing them to shake.
I'm not sure WHY anxiety causes this to happen...I'm also not sure if I don't know because I'm an ignorant 1st year medical student, or if I don't know because the mechanism behind anxiety tremors hasn't been discovered yet. Anyhow, I just thought I'd mention the phenomenon.