Caffeine addiction is common, with over 40% of the world's population consuming amounts that could be considered addictive. Caffeine is found naturally in coffee, tea, soda and chocolate. While caffeine provides alertness and mood enhancement, excessive consumption can cause sleep issues, anxiety, high blood pressure and other health problems. Those addicted to caffeine may experience withdrawal headaches and fatigue when they try to reduce their intake. Treatment involves a gradual reduction in caffeine through lifestyle changes or medication as needed.