Nicotine has an addictive effect on the brain. When one takes in nicotine it affects certain centers in the brain which causes brain to want more of nicotine. Brain is triggered to produce dopamine. This is a chemical which creates a pleasurable feeling in a person. After few days the person cannot do without nicotine, such a case faces lot of trouble getting rid of nicotine and at times could be fatal. Nicotine is very highly addictive substance and whole body is affected by the withdrawal. For a chain smoker, a heart attack or a chronic stroke is not ruled out.  During the first week of withdrawal the symptoms could be dangerous. If he holds his urge and shows strength the symptoms would start tapering off. An easy method to reduce trouble caused by withdrawal symptoms is by reducing the number of cigarettes each time he smokes. Symptoms include feeling of rigidity in chest and heavy coughing. Fatigue, effects on brain and depression can be very dangerous for a heavy smoker and need very serious attention. Insomnia and lack of rest drains the patient and also reduce the strength required to observe complete restrain over smoking. Person become mentally unstable and irritated facing difficulty in simple tasks involving concentration and attention.