In that both are legal central nervous system stimulants, we often see rationalizations that attempt to equate caffeine to nicotine. Please understand that here at Freedom it is against the forum's rules to promote drug use of any kind, including other legal stimulants. But that does not mean that we do not educate members regarding drug use rationalizations that can, and do, cross chemical lines.
Just as physical exercise is needed to stimulate the body, mental exercise, proper and regular nutrition and adequate oxygen are tools to stimulate the mind. Many of the wealthiest and most powerful minds on the planet daily stimulate their own brains, and so can we if that be our desire.
Whether or not we use caffeine or natural brain stimulation, every mental challenge we engaged while using nicotine can be accomplished without it. All of them!! Yes, there is a temporary period of re-adjustment called quitting (what many of us term "recovery") and, yes, concentrating while not using it can take a bit of practice, including re-learning to eat normally again. But once residing here on Easy Street I think you'll look back and laugh at a mind that once truly believed that it "needed" nicotine to concentrate.
For those who insist on employing rationalizations that compare drinking caffeine to smoking nicotine, according to the World Health Organization we could very well seeone billion