So look, we tend to not give to much thought about WHAT we put into our body. From the processed fatty foods we eat to the accelerants we ingest or breath in such as caffeine or nicotine. Even chocolate can trigger neurotransmitters that release chemicals to produce feelings of pleasure and reward. On this level the brain reacts like impulsive animal . . It only knows it wants to feel THIS GOOD all the time . . . Once you form the habit, the brain looks for this reoccurring interaction, when it doesn't find it at its normal; intervals, it creates that "Craving" . . .
"Recently, scientists discovered that nicotine raises the levels of a neurotransmitter called dopamine in the parts of the brain that produce feelings of pleasure and reward. Dopamine, which is sometimes called the pleasure molecule, is the same neurotransmitter that is involved in addictions to other drugs such as cocaine and heroin. Researchers now believe that this change in dopamine may play a key role in all addictions. This may help explain why it is so hard for people to stop smoking."
https://teens.drugabuse.gov/teachers/mind-over-matter/nicotine/how-does-nicotine-act-brain
