I have had PD for over 3 years and have been on various amounts of Madopar for all that time. Yesterday I decided to go on a health kick by using decaf coffee and tea. It was a mistake. I had the worse night I have ever had with both hands shaking all night, pains in both legs all night. I was awake almighty in the end I took my normal painkillers which had no effect . There is no doubt that my problems were caused by caffeine withdrawal.as far as know their are no warnings so be careful.