Caffeine use is pervasive around the world. Caffeinated beverages such as coffee, tea and soda are among the most popular drinks in the world. Caffeine, however, can have a profound effect on sleep and has been shown to both cause and worsen symptoms of insomnia and other sleep disorders. The amount of caffeine in tea, the amount of caffeine in coffee and the amount of caffeine in soda or energy drinks can vary. Caffeine, like any other drug, can be abused with dangerous results.