Caffeine withdrawal can occur after abrupt cessation of daily use. Withdrawal can occur with relatively small daily doses. The average consumption in the United States is 280 mg/day. Yet people experience withdrawal from caffeine with consumption as low 100 mg/day. The symptoms usually begin 12-24 hours after last use. The symptoms may last for 2-9 days. Symptoms include headache, fatigue and difficulty concentrating; irritable or depressed mood; and even flu-like symptoms.
Effects of Caffeine: Caffeine intoxication
Caffeine intoxication includes nervousness, restlessness, and psychomotor agitation. People may ramble while speaking and their thoughts may not be well organized. More serious effects include tachycardia and cardiac arrhythmia. Extremely high doses of caffeine can result in death. Caffeine intoxication can have other serious consequences including the inability to function at school or work, and poor judgment.