1% physical, 99% mental
Withdrawal symptoms from nicotine (the chemical that makes cigarettes addictive) are actually quite light and pass within a short time.
However, many smokers suffer for weeks, months and years after they quit, although the nicotine, and therefore the physical symptoms of it leaving the body, are long gone.
That's because the main difficulty isn’t the physical part. Rather it’s the mental addiction; they still want to smoke.
The brilliant point of difference of the Allen Carr method is it’s the only approach which helps smokers lose their desire to smoke altogether. And this is without using fear tactics or bringing up the dangers of smoking related illnesses. Remember, if you tell a smoker that smoking is bad for them and that it can kill, what's the first thing they do? They light a cigarette!
Allen Carr understood that in order to quit permanently it was essential to break the deep "connection" between cigarettes and conditions like pleasure, calmness, boredom, restlessness, stress, and the link between cigarettes and habits like coffee, alcohol, etc.
Because if an ex-smoker finds himself wanting to smoke every time he gets nervous or bored, or needs to deal with the urge to smoke every time he goes out socially he’ll never really be free.
The whole idea is to continue to do everything in your day to day life exactly the same without having even the lightest desire to smoke at all.