Anxiety
"I was switched to Effexor XR after 2 years of Paxil. It worked wonderful for about 3 years. I was on 75mg and started to have uncontrollable movement with my one arm. Talked to my doctor who said it was not the medicine. Well after another year I was having the problem in my legs and both arms and could no longer sit or walk without frequent jerking. My doctor finally realized that it was a rare side effect of the medication from long term use and switched me to another. I still have the jerking at least 2 to 3 times a week. If you notice this problem at all you need to talk to your doctor immediately."