The Neurobiology of Tobacco Addiction – Part II

Blog Post created by dr_hays on Sep 18, 2015

Last week, I introduced genetics as one factor in tobacco dependence.  Another important factor that promotes addiction is the speed and efficiency by which a drug is delivered to the brain.  The cigarette is a highly efficient delivery device for the drug nicotine.  Nicotine replacement medications are not as efficient in delivering nicotine and have comparatively very low addiction potential (1, 2).   


Tobacco companies have “improved” cigarettes by using bases like ammonia to change the pH of tobacco and enhance or “free-base” nicotine.  This allows it to travel to the brain more quickly, speeding up the delivery of nicotine and increasing its addicting potential.  The companies also manipulate the amount of nicotine in the cigarette so that they are consistent from one smoke to the next.  These once secretive practices have allowed Big Tobacco to lower the total amount of nicotine in each cigarette while increasing the percentage that is free-based (3).


Here is an informative History Channel YouTube clip that describes what goes into cigarettes: https://youtu.be/IBAuM1fLKRk


.  A drugs addictive potential is influenced by how quickly it gets to the brain.  Inhalation, or smoking, is the fastest route of delivery.  Within 7-10 seconds of smoking, free-based nicotine has seeped into the bloodstream via the lungs and has made its way into the brain where nicotine receptors reside.  As discussed in last week’s blog, chronic smoking places a demand on the brain to upregulate receptors in response to the spikes of nicotine delivered to the brain with each drag from a cigarette. 


For many people, smoking often starts as a social, pleasurable activity and grows into a frustrating cycle of dependence that can be difficult to break.  As you have read in these past two blogs, tobacco dependence is much more than a simple habit to break.  It is a physiological phenomenon that can require, persistence, time and patience to heal.  I encourage you to use every tool available to help you stop smoking.  Speak with your doctor about medications to control cravings, continue to explore BecomeAnEx, and don’t be afraid to reach out for support.  Good luck!



1.       Hughes JR, Pillitteri JL, Callas PW, Callahan R, Kenny M. Nicotine Tob Res. 2004 Feb; 6(1):79-84.

2.       Cochrane Database Syst Rev. 2004 ;(3):CD000146.

3.       WHO. The Tobacco Industry Documents 2001.