The Role of Nicotine Addiction
August 14, 2001: Smoking Cessation: Facing the Challenges of Tobacco Addiction
Jack Henningfield, Ph.D., Vice President, Pinney Associates, Bethesda, Maryland and Associate Professor of Behavioral Biology, Johns Hopkins School of Medicine, Baltimore, Maryland
Dr. Henningfield began his presentation by providing a vision of what could be possible with the tobacco epidemic if we could follow the example of how quickly the epidemic of HIV and AIDS had gone from a "death sentence" to a disease for which science-based prevention and treatment interventions were now available.
In his talk, Dr. Henningfield described the nature of tobacco addiction as a disease based on the actions of nicotine on the brain, but observed that as is the case with all drug addictions, the clinical course in individuals and the prevalence in the population is determined by more than the actions of a chemical at its target receptor. Specifically he described how the course and prevalence of tobacco addiction is influenced by factors such as marketing and advertising of tobacco products, the cost and accessibility of tobacco products, and the presence of counter forces such as treatment and education. Despite public statements to the contrary, the tobacco industry has long understood the role of nicotine in addiction and the potential for tobacco product modifications to make the products more appealing to a broader range of the population. Unfortunately, while tobacco industry documents and preliminary data from CDC and other laboratories suggest that there are many ingredients and design features in tobacco products that could contribute to their addictive potential and toxicity (e.g., ammonia additives, menthol, and smoke particle size manipulation) the base of independent science is relatively weak in this area and it is crucial that research on the products themselves be cultivated outside of the industry. This is important to public health efforts aimed at prevention and cessation and will be critical if the FDA ultimately regulates tobacco products.
The need for treatment is based on the fact that nicotine changes the structure and function of the brain, for example by increasing brain nicotine receptors in some parts of the brain by as much as 400%. These changes create a physiologically based need for nicotine, which leads the brain to dysfunction when deprived. Dysfunction can be manifested by withdrawal signs including impaired ability to concentrate and perform cognitive tasks, as well as powerful cravings. Systematic behavioral and pharmacological treatments can help people recover and make cessation possible, though rarely easy. One of the important questions being addressed by ongoing research is the degree of reversibility of the effects from decades of nicotine exposure and whether there are some individuals who will need extended if not life-long treatment to remain abstinent from tobacco.
Although the addiction to tobacco delivered nicotine can be as strong as to substances such as cocaine, heroine and alcohol, it can be treated. However, Dr. Henningfield observed, treatment of tobacco dependence can be like attempting to treat malaria in a mosquito infested swamp, because of the ease of access to tobacco products, their heavy marketing, and the fact that so many other people are themselves tobacco users. This emphasizes the importance of integrating comprehensive tobacco control activities including treatment, prevention, and the many factors important in reducing access and appeal of tobacco products, because these efforts are important to support treatment and cessation. Treatment and cessation activities, in turn, support tobacco prevention efforts.
Dr. Henningfield concluded his remarks by offering several recommendations:
- Expanded surveillance and tracking of all nicotine use and attitudes is needed to provide more rapidly disseminated and comprehensive data
- Product design and ingredient research needs to be supported by the NIH to develop the knowledge base that will be crucial for prevention and treatment, and critical if the products are regulated as emphasized in the 2001 report from the National Academy of Sciences
- FDA prioritization of tobacco addiction treatment to encourage more innovative treatment development approaches
- Expanded access and reduced barriers to treatment
- Reduced toxicity and addictiveness of tobacco products by regulating their design and ingredients
- Additional research on diversity of smokers (biological and cultural)
Following the presentation, a question was asked concerning what is known about nicotine's affect on an adolescent brain as differentiated from an adult brain. Dr. Henningfield responded that researchers are just beginning to explore this issue and the answer is important to knowing how best to treat adolescent addiction.
To a question about why FDA had not used the "fast track" and rapid review approaches for tobacco dependence treatment as it had for treatments for HIV and cancer, Dr. Henningfield acknowledged that the answer is quite complicated and there are differences of opinion on the definition of whether the condition is life threatening and whether there are already existing treatments.
A question was asked regarding individuals' varying ability to quit smoking cigarettes and whether these differences are due more to biology or unequal access to treatment services. Dr. Henningfield answered that although we need more research in this area, we do know that there are certain protective factors; such as, sports, religion, and parents that help determine one's likelihood of both starting to smoke and ability to quit.
To a question about the use of research conducted by the tobacco industry, Dr. Henningfield answered that it is both a "goldmine" and a "minefield," in that much of the research does help us understand some of the questions we should be asking. At the same time, we should remain wary of some of the results until we are able to cultivate an independent base of knowledge, particularly with respect to tobacco product ingredients and design considerations.
A final question was asked concerning the potential for a vaccine to protect the brain from addiction to tobacco. Dr. Henningfield's response was that there is a real possibility that such a vaccine could be created and NIDA is supporting research to look at this question. The trickiest issue is how to determine when and how to deliver the vaccine; for example, there are different considerations in the potential application as a preventive measure for high-risk youth than there are for application as a means of relapse prevention in adults who have achieved abstinence.
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