Tobacco (Nicotine) Use Disorder

• Tobacco use disorder is very common among individuals who use cigarettes and smokeless tobacco (e.g. - vaporizers) daily.^[1]
  • Among daily smokers, the estimated prevalence of tobacco use disorder is about 50%.^[2]
  • Tobacco use disorder is uncommon in those who are not daily users.
• In the United States, cigarettes are the most commonly used tobacco product (accounts for >90% of tobacco/nicotine use).
  • 57% of adults are never smokers, 22% are former smokers, and 21% are current smokers.^[3]
  • The prevalence of tobacco use disorder is estimated to be 13%.^[4]
• In Canada, 14.8% of the population are smokers.^[5]
• In developing countries, males significantly outnumber females in both use of tobacco and tobacco use disorder.^[6]

• More than 80% of individuals who use tobacco attempt to quit at some point in time, but over 60% will relapse within 1 week and less than 5% are able to remain abstinent for life.
  • The large majority report cravings when they do not smoke for several hours.
• Nicotine intoxication is very rare.^[7]
• 50% of smokers who do not stop tobacco will die early due to a tobacco-related illness (e.g. - heart disease, lung cancer).
  • Secondhand smoke also increases this risk by 30%.

• Individuals with schizophrenia are 2 to 4 times more likely to use tobacco (approximately 60% of all patients will smoke).^[8][9]

• Nicotine use is associated with numerous medical complications and diseases, including cancer, cardiac disease, pulmonary disease, perinatal problems (low birth weight), cough, shortness of breath, and accelerated skin aging.

• Individuals with attention-deficit/hyperactivity disorder (ADHD), conduct disorder, depressive disorders, bipolar disorders, anxiety disorders, personality disorders, psychotic disorders, and/or other substance use disorders are at higher risk of starting and continuing tobacco use and for tobacco use disorder.^[10]
• Individuals with low socioeconomic and educational background are more likely to start tobacco use.^[11]

A problematic pattern of tobacco use leading to clinically significant impairment or distress, as manifested by at least 2 of the following, occurring within a 12-month period:

1. Tobacco is often taken in larger amounts or over a longer period than was intended.
2. There is a persistent desire or unsuccessful efforts to cut down or control tobacco use.
3. A great deal of time is spent in activities necessary to obtain or use tobacco.
4. Craving, or a strong desire or urge to use tobacco.
5. Recurrent tobacco use resulting in a failure to fulfill major role obligations at work, school, or home (e.g. - interference with work).
6. Continued tobacco use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of tobacco (e.g. - arguments with others about tobacco use).
7. Important social, occupational, or recreational activities are given up or reduced because of tobacco use.
8. Recurrent tobacco use in situations in which it is physically hazardous (e.g. - smoking in bed).
9. Tobacco use is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by tobacco.
10. Tolerance, as defined by either of the following:
    • A. A need for markedly increased amounts of tobacco to achieve the desired effect.
    • B. A markedly diminished effect with continued use of the same amount of tobacco.
11. Withdrawal, as manifested by either of the following:
    • A. The characteristic withdrawal syndrome for tobacco (refer to Criteria A and B of the criteria set for tobacco withdrawal).
    • B. Tobacco (or a closely related substance, such as nicotine) is taken to relieve or avoid withdrawal symptoms.

• Nicotine is a stimulant and potent parasympathomimetic alkaloid that is naturally produced in the nightshade family of plants.
• Various formulations of nicotine can be used, including cigarettes, cigars, electronic cigarettes, oral snuff, chewing tobacco, and water pipes (“hookah”).

• Fagerstrom Test of Nicotine Dependence (FTND)
• Nicotine Dependence Syndrome Scale (NDSS)
• Wisconsin Inventory for Smoking Dependence Motives (WISDM)

• Like with all substance use disorders, there is a complex interplay between biological, social, psychological, and cultural factors.
• The nicotine in tobacco is an agonist that binds stereoselectively to nicotinic cholinergic receptors
  • Neuroimaging studies show that that nicotine increases activity in the prefrontal cortex, thalamus, and visual system.
• Chronic use of tobacco is thought to increase the number of nicotinic cholinergic receptors binding sites in the brain.
• The upregulation of receptors is thought to be due to nicotine-mediated desensitization of receptors, and the desensitization may play a role in nicotine tolerance and dependence.^[12][13]

• The metabolite cotinine can be detected in blood, saliva, or urine (but is only weakly related to tobacco use disorder).

• Combining counselling/psychotherapy/behavioural approaches with pharmacotherapy is better than doing either treatment alone.
  • Comprehensive treatment approaches are required, with supportive counselling from a healthcare provider such as following the Ottawa Model for Smoking Cessation (OMSC).^[14]
• In general, the most effective to least effective medications are: varenicline, followed by bupropion, then nicotine replacement therapy.

• Nicotine replacement therapy (NRT) is recommended with either nicotine replacement first, followed by non-nicotine pharmacotherapies such as varenicline or bupropion.
  • For patients who smoke intermittently, NRT such as nicotine lozenges or gum can be used on an as needed basis.
  • For patients who smoke more frequently, such as several times per day, they will need consistent nicotine replacement from a patch to prevent the peaks and troughs associated with nicotine cravings.

• If the individual is a heavy smoker, or there are withdrawal symptoms despite nicotine replacement (e.g. - cravings, irritability, frustration, anger, anxiety, difficulty concentrating, and/or restlessness), consider adding non-nicotine pharmacotherapies such as:
  • Bupropion SR is an NDRI that increases dopaminergic activity, which may relate to its anti-smoking efficacy. It should not be prescribed to patients with a history of seizures!
    • Start most patients at 150 mg in the morning and increase to twice daily dosing as tolerated.
  • Varenicline
    • Varenicline works as a partial agonist/antagonist of nicotine receptors. The nicotine stimulation works by stimulating nicotine receptors, blocking the dopamine effects, and thereby decreasing the reward or enjoyment a patient feels while smoking.
      • This decrease in gratification helps curb smoking over time, allowing for more successful cessation.
    • Using varenicline in conjunction with a nicotine replacement patch is better than varenicline alone.^[15]

• Adding behavioural and psychological treatments to pharmacotherapy increases the chance of stopping use successfully (long-term abstinence rates approach 25 to 30%).