The smoker feels a strong urge to smoke when the body-mind is agitated. Nicotine response makes the brain increase the endorphins. The endorphins satisfy and calm the mind. After a few hours the endorphin levels drop. The body-mind gets agitated and frustrated; the attention span to accomplish any work is not there. The craving for a cigarette becomes very strong. Once a cigarette is smoked the endorphins level is high, the body-mind system calms down. This is an ongoing process that can last a lifetime. The nicotine enforces this pattern. The chart below shows the high and low endorphin patterns from the nicotine addiction.