2007 Johns Hopkins Bloomberg School of Public Health Tobacco Addiction Jack E. Henningfield, PhD...
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Transcript of 2007 Johns Hopkins Bloomberg School of Public Health Tobacco Addiction Jack E. Henningfield, PhD...
2007 Johns Hopkins Bloomberg School of Public Health
Tobacco AddictionTobacco Addiction
Jack E. Henningfield, PhDJohns Hopkins School of MedicinePinney Associates
2 2007 Johns Hopkins Bloomberg School of Public Health
Addiction Terminology
Addiction: common term applied to maladaptive drug-seeking behavior Equivalent to American Psychiatric Association
(APA)/World Health Organization (WHO) “dependence”
Dependence: APA refers to “nicotine,” while WHO refers to “tobacco” amount delivered to the person
3 2007 Johns Hopkins Bloomberg School of Public Health
Addiction Terminology
Withdrawal: transient symptoms following abstinence when physical dependence is present (i.e., neuroadaptation)
Tolerance: decreased response to repeated doses
Dependence, withdrawal, and tolerance can occur independently
Withdrawal and tolerance are neither necessary nor sufficient for dependence
4 2007 Johns Hopkins Bloomberg School of Public Health
Cigarettes Are among the Most Addictive Drugs
Addiction risk following use and addiction in current users: Cigarettes > Cocaine > Opioids > Alcohol
Image source: adapted by CTLT from U.S. National Academy of Science, Institution of Medicine. (1999).
5 2007 Johns Hopkins Bloomberg School of Public Health
Trajectory of Tobacco Use
6 2007 Johns Hopkins Bloomberg School of Public Health
Tobacco Related Deaths
Image source: Jack Henningfield.
7 2007 Johns Hopkins Bloomberg School of Public Health
Smoke for Nicotine; Die from Smoke
“Smoke for nicotine; die from smoke”—Michael A.H. Russell
Image source: Jack Henningfield.
8 2007 Johns Hopkins Bloomberg School of Public Health
All Tobacco Products Are Deadly and Addictive
Image source: Institute for Global Tobacco Control.
9 2007 Johns Hopkins Bloomberg School of Public Health
Up in Tobacco Smoke
Most cigarettes contain about 10 mg nicotine
Bioavailability: 10–40% typical dose is 1–3 mg nicotine per cigarette, regardless of whether it is advertised as “light” or “regular”
Tar (or TPM) comes from the burning (pyrolysis) of tobacco; the particles in smoke are in the size range (< one micron) that enters the lung
CO is a pyrolysis product; its half life varies with respiratory rate but it is typically four to seven hours in expired air or COHb tests
10 2007 Johns Hopkins Bloomberg School of Public Health
Quotes
“Free nicotine is absorbed more rapidly by the smoker than is bound nicotine” RJR, Rodgman (1980)
“As the pH increases, the nicotine changes its chemical form so that it is more rapidly absorbed by the body and more quickly gives a ‘kick’ to the smoker” McKenzie (1976); Minn. Trial Exhibit 12,270
“AT [ammonia technology] is the key to competing in smoke quality with PM [Philip Morris] world-wide” B&W, Johnson (1989)
11 2007 Johns Hopkins Bloomberg School of Public Health
Quotes
Low tar cigarettes “Provide smokers with a choice and a
reason not to quit”— Brown & Williamson (1979)
“. . . the effect of switching to low tar cigarettes may be to increase, not decrease, the risks of smoking”— BAT, Lee (1979)
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Light Cigarettes
“Light” cigarettes are more ventilated and more readily enable compensatory smoking
Ventilation holes
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Menthol Light Cigarettes
Product design and ingredients (menthol) converge to produce cooler, smoother smoke
This is a deadly and deceptive marketing ploy because the cigarettes are as toxic as “full flavor” cigarettes
Image source: Tobacco Documents Online. Permission granted for educational use.
14 2007 Johns Hopkins Bloomberg School of Public Health
The “Ultimate” Chemical Cocktail
Tobacco-delivered nicotine Most addictive Most toxic Explosively fast delivery Optimal particle size to deposit in the lung pH controlled Sensory “optimization” Chemical cocktail designed to addict
Ammonia increases dose Acetaldehyde synergy “Smoothing” menthol MAO (monoamine oxidase) inhibiting effects
15 2007 Johns Hopkins Bloomberg School of Public Health
Neurobiology of Nicotine and Other Drugs
Like other abused drugs, nicotine stimulates brain reward pathways and increases dopamine in the nucleus accumbens in the brain
Effects in the brain reinforce behavior, alter mood, and create a need that did not exist prior to drug exposure
16 2007 Johns Hopkins Bloomberg School of Public Health
Other Effects Contribute to Tobacco Use
Reduces anxiety and relieves stress and boredom
Improves performance and attention or at least reverses withdrawal deficits
Decreases appetite
Helps start car and answer phone?
The ubiquitous association of smoking with daily living leads to powerful behavioral conditioning
17 2007 Johns Hopkins Bloomberg School of Public Health
Blood Nicotine Concentration
Nicotine levels fluctuate widely, beginning at low levels after sleeping and rising throughout the day
Waking is accompanied by early signs of withdrawal—with stronger cravings in more dependent smokers
Image source: Jack Henningfield.
18 2007 Johns Hopkins Bloomberg School of Public Health
Damaging Effects of Tobacco
Nicotine in the brain leads to addiction
Image source: Jack Henningfield.
19 2007 Johns Hopkins Bloomberg School of Public Health
Effects of Four Drugs on Dopamine Levels
Image sources: adapted by CTLT from (top left to bottom right) Ponberi, F. E., et al. (1996); Melega et al. (1995); Tanda et al. (1997).
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Nicotine Receptor Modulation
Image source: Jack Henningfield.
Nicotine receptor modulation produces cascading effects via neurohormones
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Nicotine Receptors Upregulate
Nicotine receptors upregulate: reversibility in chronic smokers unclear
Image source: Jack Henningfield.
22 2007 Johns Hopkins Bloomberg School of Public Health
Increased receptors associated with tolerance and dependence
Increased Receptors
Image source: Jack Henningfield.
23 2007 Johns Hopkins Bloomberg School of Public Health
Brain of Nonsmoker Versus Brain of Smoker
Autopsy studies comparing smokers to nonsmokers reveal up to 400% increases in brain nicotine receptors
Reversibility extent, time course, and variability is unclear
Text source: Perry, D., et al. (1999); Image source: Journal ofPharmacology and Experimental Therapeutics. (1999).
Temporal cortex
Prefrontal cortex
Hippocampus
Nonsmoker
Smoker
24 2007 Johns Hopkins Bloomberg School of Public Health
Nicotine Withdrawal and Dysfunction of the Brain
Nicotine withdrawal is associated with dysfunction of the brain and performance, but it can be treated
Nicotine replacement and other therapies are available
25 2007 Johns Hopkins Bloomberg School of Public Health
Withdrawal Can Be Treated
Source: adapted by CTLT from Synder, F. and Henningfield, J. (1998).
26 2007 Johns Hopkins Bloomberg School of Public Health
Medications (2006)
NRTs Gum Lozenge Patch (several types) Nasal Oral “inhaler”
Nicotinic Varenicline
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Medications (2006)
In development Rimonabant Vaccines New nicotine replacement therapies (NRTs) New medications
28 2007 Johns Hopkins Bloomberg School of Public Health
Advertisement
Image source: Tobacco Documents Online (TobaccoDocuments.org). Permission granted for educational use.
29 2007 Johns Hopkins Bloomberg School of Public Health
Regional cerebral blood flow (rCBF)
fMRI: BOLD STUDY: Severity of nicotine dependence modulates cue-induced brain activity in regions involved in motor preparation and imagery. Psychopharmacology.
Brain Imaging Studies
Smoking, withdrawal, and evoked cravings affect brain function as assessed by imaging techniques including PET and fMRI
Image source: Zubieta, et al. (2005); Smolka, et al. (2005). No permission granted.
30 2007 Johns Hopkins Bloomberg School of Public Health
Summary
Nicotine is highly addictive, and it is most addictive when delivered in the form of tobacco products
Nicotine affects receptors in the brain and causes addiction
People who try to give up tobacco are fighting biology
Health professionals need to address the physical side of addiction
Treatment of addiction and prevention of smoking should go hand in hand