A 96-year-old patient was admitted for a hip fracture. Upon entering the operating room, he was very agitated, restless, and insistently asked for a cigarette. When he was finally allowed to smoke, he calmed down and became stable. This illustrates a case of nicotine withdrawal. Nicotine affects the central nervous system by stimulating neurotransmitters such as dopamine and acetylcholine. Chronic exposure leads to dependence, and sudden cessation causes a sharp drop in these neurotransmitters.