Caffeine withdrawal

**Definition:** Caffeine withdrawal is a clinically significant cluster of symptoms, behaviours and/or physiological features, varying in degree of severity and duration, that occurs upon cessation or reduction of use of caffeine (typically in the form of coffee, caffeinated drinks, or as an ingredient in certain over-the-counter medications) in individuals who have used caffeine for a prolonged period or in large amounts. Presenting features of Caffeine withdrawal may include headache, marked fatigue or drowsiness, irritability, depressed or dysphoric mood, nausea or vomiting, and difficulty concentrating.