Withdrawal from Nicotine Underlying Cause
Nicotine withdrawal occurs because the body is physically dependent on the effects of nicotine. When nicotine is stopped, the body must adjust to the absence of the nicotine. Nerves throughout the body become excessively stimulated without the drug, which results in the symptoms of withdrawal.
- Berrettini WH, Lerman CE. Pharmacotherapy and pharmacogenetics of nicotine dependence. Am J Psychiatry. 2005 Aug;162(8):1441-51. 
- Gonzales D, Rennard SI, Nides M, Oncken C, Azoulay S, Billing CB, Watsky EJ, Gong J, Williams KE, Reeves KR; Varenicline Phase 3 Study Group. Varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, vs sustained-release bupropion and placebo for smoking cessation: a randomized controlled trial. JAMA. 2006 Jul 5;296(1):47-55. 
- Mooney ME, Sofuoglu M. Bupropion for the treatment of nicotine withdrawal and craving. Expert Rev Neurother. 2006 Jul;6(7):965-81. 
- Shiffman S, Fant RV, Buchhalter AR, Gitchell JG, Henningfield JE. Nicotine delivery systems. Expert Opin Drug Deliv. 2005 May;2(3):563-77.