One of the reasons is the nicotine found in cigarettes affects dopamine, a neurotransmitter in the brain that is also known as the reward pathway.
“Nicotine excites that reward pathway enough that it gets people thinking, ‘Oh, I really need that cigarette. Oh, I really want that cigarette,’” Dr. Springs says. “It’s almost as if their brain is telling them they should keep smoking.”
Social influences such as advertising and peer groups also impact the ability to quit. Teens, for instance, may smoke if it seems a way to be socially accepted. Adults may align themselves with a group of friends or co-workers who have the same habit.