Chapter 7 - Nicotine

Nicotine & Tobacco

  • 60 species of Nicotiana

    • only 2 can be used for smoking/human consumption

      • Nicotiana rustica

      • Nicotiana tabacum

        • provides all tobacco in US

  • tobacco has many ingredients

    • nicotine is the main drug in tobacco

    • nicotine is extremely toxic

      • approximately as toxic as cyanide

      • lighting it (smoking) makes it less quantity so not toxic that way

Tobacco Use History

  • indigenous to South America

  • flourished in Virginia

  • popular in Europe

  • attempts to suppress tobacco smoking failed

    • church - considered a vice

  • tobacco was believed to have medicinal value

Prevalence of Tobacco

  • more males smoked than females

  • as education level increases, rate of smoking decreases

  • unemployed people smoke more

Prevalence of Cigarettes

Prevalence of E-Cigarettes

Prevalence of Tobacco: Middle School/High School

Starting Smoking

  • the earlier a person starts to smoke, the harder it is to quit later

  • adolescent dependence on nicotine persists into adulthood

  • advertising targeted to groups is associated with smoking initiation in those groups

  • the adolescent brain is more sensitive to reinforcing effects of nicotine

  • PET scan studies show greater effects of nicotine in people with hostile or aggressive personalities

  • novelty-seeking adolescents are more receptive to tobacco ads

Pharmacology: Sites of Action

  • nicotine mimics acetylcholine (ACH)

    • ACH acts on autonomic nervous system & the central nervous system

    • nicotine has biphasic effects - at low amounts: increase acetylcholine system, at high amounts: decrease

  • interacts with dopamine system

    • increase extracellular dopamine in nucleus accumbens

  • interacts with GABA, NE & 5-HT systems

    • leads to increase of norepinephrine, serotonin, & endorphins

  • may self-medicate for attention

Pharmacokinetics

  • absorption

    • nicotine is readily absorbed across all body membranes

    • site of contact and length of time tobacco contacts membranes affect absorption

  • distribution: quick

  • metabolism

    • nicotine is excreted in all body fluids, but mostly in urine

    • as nicotine levels drop, smokers experience withdrawal

  • people tend to re-dose throughout the day

Developing Dependence

  • not clear why tobacco use is reinforcing

    • for most, smoking isn’t pleasant at first

      • psychosocial rewards

    • most can’t describe an attractive effect except taste of tobacco

  • past: “nicotine is the reinforcing factor behind smoking”

    • low doses (0.01 mg/kg; IV) → mood enhancement & drug liking

    • high doses (0.04 mg/kg; IV) → aversive

    • nicotine increase dopamine concentrations in nucleus accumbens

  • if nicotine is the only factor, nicotine gum should be 100% effective

    • it isn’t

    • now, many view smoking’s ability to decrease negative feelings as important

      • e.g., sadness, boredom, anxiety, environment

      • nicotine also relives nicotine withdrawal

Tolerance & Dependence

  • Tolerance

    • develops quickly

      • within the first few cigarettes ever smoked

      • within the first few cigarettes of the day

  • dependence

    • physical dependence

      • withdrawal symptoms

        • craving, irritability, anxiety

        • difficulty concentrating, restlessness

        • increase appetite and insomnia

      • risk increases with regular smoking

    • psychological dependence

Effects

  • users typically report smoking calms them & decrease tension

    • cognitive effects often comparable to caffeine

    • EEG patterns consistent with increased psychological arousal

  • facilitates

    • finger-tapping rate & choice reaction time

    • focused & sustained attention

    • recognition memory & short-term memory

    • vigilance

    • motor tracking

    • decreased deprivation induced deficits

  • impairs

    • complex task performance

    • solving problems

    • understanding articles

  • to date, no true increase in

    • sensory abilities

    • selective attention

    • problem solving or reasoning

  • acute effects

    • mimic ACH
      enhances alertness, learning, memory

    • increases heart rate, blood pressure, heart contraction

    • relaxes skeletal muscles

    • decreases appetite for sweet food

  • chronic use effects

    • life-threatening diseases

      • lung & oral cancers

      • emphysema

      • heart disease and stroke

    • pregnancy complications

  • warnings on boxes: changed in rotation because if same warning every time, people will ignore

Tobacco Culprits

  • cigarette smoking damages health because of the constituents of tobacco smoke

  • 3 main culprits

    • tar

    • nicotine

    • carbon monoxide

  • are cigarettes low in tar and nicotine safer?

    • no

  • passive smoke?

    • secondhand smoke: Group A carcinogen

    • thirdhand smoke: toxins deposited onto hair, clothing - especially bad for young children whose immune systems are not fully developed

Is Vaping Safer?

  • nope

  • still addictive, has nicotine still

  • has carcinogen

  • fun flavors to entice

Why is Quitting Hard?

  • motivation to quit

  • influences on relapse

  • most people who quit do so without treatment

    • but, they make many attempts

  • treatment goals

    • control nicotine withdrawal

    • break habits of movements used in smoking

    • learn coping skills

  • increased nicotine receptors for a little after quitting

Treatments

  • behavioral programs

    • individual or group therapy

    • effective compared to placebo

    • high relapse rates

    • historically involved ongoing, direct, often weekly contact with clinical staff in group or individual format for 2-3 months

      • teach clients to identify high risk situations

      • apply techniques to weaken habit components, teach competing coping responses

      • teach self-monitoring

    • successful, but not practical or afforable for many

      • recent expansion in format, intensity, duration of programs

    • overall effective way to stop smoking

      • incorporated in APA’s guidelines for treatment of cigarette smoking

  • nicotine replacement

    • gum, patch, nasal spray, inhaler, lozenge

    • all double chances of quitting

    • more effective when combined with behavioral programs

    • generally safe long-term

    • relapse has been attributed to nicotine cravings

    • each of the NRTs doubles the chances of quitting compared to placebo

    • research finds no differences in effectiveness of different NRTs

      • individuals may initially prefer a certain NRT over others, but typically adapt to the one they are using

      • combining NRTs with behavioral programs enhances quit rates of either treatment alone

    • little evidence of long term negative consequences of using NRTs as intended

  • pharmacological

    • bupropion (Zyban)

      • antidepressant

      • not nicotine-based

      • superior to placebo

      • other antidepressants have not been effective for smoking cessation

    • varenicline (Chantix)

      • competes with nicotine to bind to receptors

        • nicotine receptor partial agonist

      • reduces cravings & effectiveness of nicotine

  • informational campaigns and “macro-environmental” methods have lowered smoking prevalence and number of people exposed to secondhand and thirdhand smoke

    • prevention programs aimed at youth who have not started smoking yet are best

      • tobacco use is hard to stop once started

      • tobacco industry advertising is a major counterforce against prevention programs

    • continue expansion of smoking treatment formats

      • new worksite treatments have proven effective

      • brief behavioral or NRT for adults, teens in primary medical care settings

      • “precision medicine” - genetic marker matching

      • “harm reduction”