The neurobiology of the addicted brain is complex. The addicted brain is definitely different than a nonaddicted brain. Acute changes in a drug-addicted brain is characterized by a dopamine surge in the nucleus accumbens mediated by the mesolimbic dopamine system. Nicotine is more addictive than cocaine or heroin. Nicotine reaches the brain within 10 seconds after inhalation from a cigarette.
Nicotine affects both reward and withdrawal behavior.
The neurobiologic hallmark of addiction is the dopamine surge in the nucleus accumbens. Dopaminergic effects in the nucleus accumbens are involved in the pleasure or reward pathway whereas noradrenergic effects in the locus ceruleus are involved in enhancing intellect and feeds the withdrawal behavior. Consequently, any treatment for tobacco dependence must treat nicotine addiction and must remedy the motivational state to repeat a behavior that leads to repetitive and compulsory drug use. The essentials of treatment require accurate diagnosis of nicotine dependence. Treatment must be individualized with rational dosing of pharmacological aids for smoking cessation, counseling of the patient with ongoing support, and encouragement to continue the motivation to quit.