The Science of Nicotine Addiction
What Is Nicotine Addiction
Nicotine enters your bloodstream via your lungs when you smoke or vape, and quickly reaches your brain, where it exerts its addictive effects. Nicotine stimulates dopamine production and release. Dopamine is a neurotransmitter, the most important chemical in our brain’s reward and pleasure pathways. We enjoy smoking because nicotine triggers the activity of your brain’s reward centers by increasing dopamine production.
Your brain will develop an addiction to nicotine after only a few exposures. This is because your brain quickly adjusts to the increased dopamine production caused by nicotine, and reduces other pathways so that your dopamine levels remain stable. This means that smokers need nicotine to maintain normal brain dopamine levels. This also means that smokers only really feel comfortable when they have nicotine in their system.
When you smoke, you also develop a non-chemical, psychological addiction to nicotine. This is based on the rituals, habits, feelings and friendships you previously associated with smoking. Psychological smoking addiction can be just as hard to break as the physical addiction to nicotine.
Cravings
Dopamine at a neuronal junction in the brain. When dopamine is released, it stimulates dopamine receptors on other neurons, exciting the reward pathways in the brain
Cravings are what a smoker experiences when blood nicotine levels become lower than what their brain has adjusted to.
The longer you smoke, and the more you smoke, the more your brain will depend on nicotine to maintain healthy dopamine levels. This is why heavy or long-term smokers experience earlier (and worse) cravings and nicotine withdrawal symptoms than light smokers.
Cravings are strong and subtle at the same time, as your brain finds ways to remind you it needs nicotine. Some people find smoking a subconscious habit; their brain has experienced subtle cravings and reminded them to light up without them even realising. Experiencing cravings, or simply wanting to avoid or stave them off, is one aspect of smoking that makes it so addictive. It becomes easy to just take another cigarette and think about quitting later. The unpleasantness of cravings when you do not smoke, and the stimulation of reward pathways when you do smoke, makes nicotine a highly addictive substance.
Withdrawal Symptoms
Nicotine withdrawal is what your body experiences as the nicotine levels in your body decrease.
It is unpleasant as your brain struggles to generate enough dopamine to effectively run your pleasure and reward pathways without the support of nicotine. After a long enough period (normally about 1 week), your brain will have re-adjusted to life without nicotine, and you will be able to produce healthy levels of dopamine again.
Nicotine withdrawal can be intense, lasting several days before symptoms decrease in severity. Nicotine withdrawal symptoms include the following:
Symptoms
- Shakes
- Constipation
- Increased appetite
- Depression, anxiety and irritability
- Difficulty concentrating
- Cravings
Cutting down or using nicotine replacement therapies (NRTs) like patches and e-cigarettes will help reduce withdrawal symptoms, increasing your likelihood quitting successfully.
What Affects Your Likelihood of Addiction?
Research has shown different people can be more or less likely to become addicted to smoking. How severe your addiction is, how severe your withdrawal is, and how long your nicotine withdrawal lasts, all depends on several factors. Among others, your risk of nicotine addiction is affected by:
Outlook
Nicotine addiction has one of the hardest withdrawals to overcome, due to its combination of physical and psychological impacts [6].
Almost every person looking to quit smoking will have to quit and relapse several times before they are successful [7]. But, research shows that this is all part of the quitting process. Studies show, the longer you quit in each attempt, the more likely you will quit forever [8].
Sources
References & Citations
- Journal of Smoking Cessation. Volume 9, Issue 2 December 2014 , pp. 53-59
Nicotine: Pharmacology, Toxicity and Therapeutic use. Karl Fagerström
https://www.cambridge.org/core/journals/journal-of-smoking-cessation/article/nicotine-pharmacology-toxicity-and-therapeutic-use/15D8BBF6393C6093C2076546E6515457 - Pharmacol Rev. 2005 Mar;57(1):79-115. Metabolism and disposition kinetics of nicotine. Hukkanen J1, Jacob P 3rd, Benowitz NL.
https://www.ncbi.nlm.nih.gov/pubmed/15734728/ - Benowitz, Neal L. “Nicotine addiction” New England journal of medicine vol. 362,24 (2010): 2295-303.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2928221/ - Smoking and mental illness: A population-based prevalence study. Lasser K, Boyd JW, Woolhandler S, Himmelstein DU, McCormick D, Bor DH JAMA. 2000 Nov 22-29; 284(20):2606-10.
https://www.ncbi.nlm.nih.gov/pubmed/11086367/ - Sex differences in long-term smoking cessation rates due to nicotine patch.
Perkins KA, Scott J Nicotine Tob Res. 2008 Jul; 10(7):1245-50
https://www.ncbi.nlm.nih.gov/pubmed/18629735/ - DiFranza, J., & Ursprung, W. W. (2010). A systematic review of the international classification of diseases criteria for the diagnosis of tobacco dependence. Addictive Behaviors, 35, 805–810.
https://www.ncbi.nlm.nih.gov/pubmed/20493638 - Bold KW, Rasheed AS, McCarthy DE, Jackson TC, Fiore MC, Baker TB. Rates and predictors of renewed quitting after relapse during a one-year follow-up among primary care patients. Ann Behav Med. 2015;49(1):128-40.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4223110/ - McLaughlin I, Dani JA, De Biasi M. Nicotine withdrawal. Curr Top Behav Neurosci. 2015;24:99-123.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4542051/
Images
http://www.publicdomainfiles.com/show_file.php?id=14000169022104
– National Institute on Drug Abuse
