Smoking cessation

It is common for ex-smokers to have made a number of attempts (often using different approaches on each occasion) to stop smoking before achieving long-term abstinence. According to a recent survey from UNC over 74.7% of smokers attempt to quit without any assistance,[16] otherwise known as "Cold Turkey", or with home remedies. A recent study estimated that ex-smokers make between 6 and 30 attempts before successfully quitting.[15] Identifying which approach or technique is eventually most successful is difficult; it has been estimated, for example, that only about 4% to 7% of people are able to quit smoking on any given attempt without medicines or other help.[2][17] A recent review of unassisted quit attempts in 9 countries found that the majority of quit attempts are still unassisted, though the trend seems to be shifting. In the U.S., for example, the rate of unassisted quitting fell from 91.8% in 1986 to 52.1% during 2006 to 2009.[18] The most frequent unassisted methods were "cold turkey", a term that has been used to mean either unassisted quitting or abrupt quitting[18] and "gradually decreased number" of cigarettes, or "cigarette reduction".[3]

"Cold turkey" is a colloquial term indicating abrupt withdrawal from an addictive drug, and in this context indicates sudden and complete cessation of all nicotine use. In three studies, it was the quitting method cited by 76%,[19] 85%,[20] or 88%[21] of long-term successful quitters. In a large British study of ex-smokers in the 1980s, before the advent of pharmacotherapy, 53% of the ex-smokers said that it was "not at all difficult" to stop, 27% said it was "fairly difficult", and the remaining 20% found it very difficult.[22] Studies have found that two-thirds of recent quitters reported using the cold turkey method and found it helpful.[23]

A 21mg dose nicotine patch applied to the left arm.

The American Cancer Society notes that "Studies in medical journals have reported that about 25% of smokers who use medicines can stay smoke-free for over 6 months."[24] Single medications include:

• Nicotine replacement therapy (NRT): Five medications have been approved by the U.S. Food and Drug Administration (FDA) deliver nicotine in a form that does not involve the risks of smoking: transdermal nicotine patches, nicotine gum, nicotine lozenges, nicotine inhalers, nicotine oral sprays, and nicotine nasal sprays.[25] High-quality evidence indicates that these forms of NRT improve the success rate for people who attempt to stop smoking.[26] NRTs are meant to be used for a short period of time and should be tapered down to a low dose before stopping. NRTs increase the chance of stopping smoking by 50 to 60% compared to placebo or to no treatment.[25] Some reported side effects are local slight irritation (inhalers and sprays) and non-ischemic chest pain (rare).[25][27] Others include mouth soreness and dyspepsia (gum), nausea or heartburn (lozenges), as well as sleep disturbances, insomnia, and a local skin reaction (patches).[27][28]

A study found that 93% of over-the-counter NRT users relapse and return to smoking within six months.[29]

There is weak evidence that adding mecamylamine to nicotine is more effective than nicotine alone.[30]

• Antidepressants: The antidepressant bupropion is considered a first-line medication for smoking cessation and has been shown in many studies to increase long-term success rates. Although bupropion increases the risk of getting adverse events, there is no clear evidence that the drug has more or less adverse effects when compared to placebo. Nortriptyline produces significant rates of abstinence versus placebo.[31]
• Other antidepressants such as selective serotonin reuptake inhibitors (SSRIs) and St. John's wort have not been consistently shown to be effective for smoking cessation.[31]
• Varenicline decreases the urge to smoke and reduces withdrawal symptoms and is therefore considered a first-line medication for smoking cessation.[32] A 2016 Cochrane review of 27 studies also found that the number of people stopping smoking with varenicline was higher than with bupropion or NRT.[33] Varenicline more than doubled the chances of quitting compared to placebo, and was also as effective as combining two types of NRT. 2 mg/day of varenicline has been found to lead to the highest abstinence rate (33.2%) of any single therapy, while 1 mg/day leads to an abstinence rate of 25.4%. A 2016 systematic review and meta-analysis of randomized controlled trials concluded there is no evidence supporting a connection between varenicline and increased cardiovascular events.[34] Concerns arose that varenicline may cause neuropsychiatric side effects, including suicidal thoughts and behavior.[33] However, more recent studies indicate less serious neuropsychiatric side effects. For example, a 2016 study involving 8,144 patients treated at 140 centers in 16 countries "did not show a significant increase in neuropsychiatric adverse events attributable to varenicline or bupropion relative to nicotine patch or placebo".[35] A 2016 Cochrane review concluded that the most recent evidence does not indicate that there is a link between depressed moods, agitation or suicidal thinking in smokers taking varenicline to decrease the urge to smoke.[33] For people who have pre-existing mental health difficulties, varenicline may slightly increase the risk of experiencing these neuropsychiatric adverse events.[33]
• Clonidine may reduce withdrawal symptoms and "approximately doubles abstinence rates when compared to a placebo", but its side effects include dry mouth and sedation, and abruptly stopping the drug can cause high blood pressure and other side effects.[12][36]
• There is no good evidence anxiolytics are helpful.[37]
• Previously, rimonabant which is a cannabinoid type 1 receptor antagonist was used to help in quitting and to moderate the expected weight gain.[38] But it is important to know that the manufacturers of rimonabant and taranabant stopped production in 2008 due to its serious side effects.[38]

The 2008 US Guideline specifies that three combinations of medications are effective:[12]^:118–120

• Long-term nicotine patch and ad libitum NRT gum or spray
• Nicotine patch and nicotine inhaler
• Nicotine patch and bupropion (the only combination that the US FDA has approved for smoking cessation)

A meta-analysis from 2018, conducted on 61 RCTs, showed that during their first year of trying to quit, approximately 80% of the participants in the studies who got drug assistance (bupropion, NRT, or varenicline) returned to smoking while 20% continued to not smoke for the entire year (i.e.: remained sustained abstinent).[9] In comparison, 12% the people who got placebo kept from smoking for (at least) an entire year.[9] This makes the net benefit of the drug treatment to be 8% after the first 12 months.[9] In other words, out of 100 people who will take medication, approximately 8 of them would remain non-smoking after one year thanks to the treatment.[9] During the course of one year, the benefit from using smoking cessation medications (Bupropion, NRT, or Varenicline) decreases from 17% in 3 months, to 12% in 6 months to 8% in 12 months.[9]

Gradual reduction involves slowly reducing one's daily intake of nicotine. This can theoretically be accomplished through repeated changes to cigarettes with lower levels of nicotine, by gradually reducing the number of cigarettes smoked each day, or by smoking only a fraction of a cigarette on each occasion. A 2009 systematic review by researchers at the University of Birmingham found that gradual nicotine replacement therapy could be effective in smoking cessation.[39][40] A 2019 Cochrane review found no significant difference in quit rates between smokers who quit by gradual reduction or abrupt cessation as measured by abstinence from smoking of at least six months from the quit day. The same review also looked at five pharmacological aids to reduction. When reducing the number of smoked cigarettes, it found some evidence that additional Varenicline or fast-acting Nicotine replacement therapy can have positive effects on quitting for six months and longer.[41]

Most smoking cessation resources such as the Centers for Disease Control and Prevention (CDC)[42] and The Mayo Clinic[43] encourage smokers to create a quit plan, including setting a quit date, which helps them anticipate and plan ahead for smoking challenges. A quit plan can improve a smoker's chance of a successful quit[44][45][46] as can setting Monday as the quit date, given that research has shown that Monday more than any other day is when smokers are seeking information online to quit smoking[47] and calling state quit lines.[48]

A Cochrane review found evidence that community interventions using "multiple channels to provide reinforcement, support and norms for not smoking" had an effect on smoking cessation outcomes among adults.[49] Specific methods used in the community to encourage smoking cessation among adults include:

• Policies making workplaces[19] and public places smoke-free. It is estimated that "comprehensive clean indoor laws" can increase smoking cessation rates by 12%–38%.[50] In 2008, the New York State of Alcoholism and Substance Abuse Services banned smoking by patients, staff, and volunteers at 1,300 addiction treatment centers.[51]
• Voluntary rules making homes smoke-free, which are thought to promote smoking cessation.[19][52]
• Initiatives to educate the public regarding the health effects of second-hand smoke,[53] including the significant dangers of secondhand smoke infiltration for residents of multi-unit housing.[54]
• Increasing the price of tobacco products, for example by taxation. The US Task Force on Community Preventive Services found "strong scientific evidence" that this is effective in increasing tobacco use cessation [55]^:28–30 It is estimated that an increase in price of 10% will increase smoking cessation rates by 3–5%.[50]
• Mass media campaigns. The US Task Force on Community Preventive Services declared that "strong scientific evidence" existed for these when "combined with other interventions",[55]^:30–32 and a Cochrane review suggested their benefits with paying attention to their intensity and duration.[56]
• Institutional level smoking bans. A recent Cochrane Review found evidence that imposing bans at the institutional level (i.e. hospitals and prisons) reduced smoking rates and secondhand exposure, although the evidence base was rated as poor quality.[57]

• The Great American Smokeout is an annual event that invites smokers to quit for one day, hoping they will be able to extend this forever.
• The World Health Organization's World No Tobacco Day is held on May 31 each year.
• Smoking-cessation support is often offered over the telephone quitlines[58][59] (e.g., the US toll-free number 1-800-QUIT-NOW), or in person. Three meta-analyses have concluded that telephone cessation support is effective when compared with minimal or no counselling or self-help, and that telephone cessation support with medication is more effective than medication alone,[12]^:91–92[55]^:40–42 and that intensive individual counselling is more effective than the brief individual counselling intervention.[60] A small tendency towards better results for more intensive counselling was also observed in another meta-analysis. This analysis distinguished between reactive (smokers calling quitlines) and proactive (smokers receiving calls) interventions. For people who called the quitline themselves, additional calls helped to quit smoking for six months or longer. When proactively initiating contact with a smoker, telephone-counselling increased chances of smoking cessation by 2-4% compared with people who received no calls.[61] There is about 10% to 25% increase of the chance of smoking cessation success with the more behavioral support provided in person or via telephone when used as an adjunct to pharmacotherapy.[62]
• Online social cessation networks attempt to emulate offline group cessation models using purpose built web applications. They are designed to promote online social support and encouragement for smokers when (usually automatically calculated) milestones are reached. Early studies have shown social cessation to be especially effective with smokers aged 19–29.[63]
• Group or individual psychological support can help people who want to quit. Recently, group therapy has been found to be more helpful than self-help and some other individual intervention.[64] The psychological support form of counselling can be effective alone; combining it with medication is more effective, and the number of sessions of support with medication correlates with effectiveness.[12]^{:89–90,101–103}[65][66] The counselling styles that have been effective in smoking cessation activities include motivational interviewing,[67][68][69] cognitive behavioral therapy[70] and Acceptance and Commitment Therapy,[71] methods based on Cognitive Behavioral Therapy.
• The Freedom From Smoking group clinic includes eight sessions and features a step-by-step plan for quitting smoking. Each session is designed to help smokers gain control over their behavior. The clinic format encourages participants to work on the process and problems of quitting both individually and as part of a group.[72]
• Multiple formats of psychosocial interventions increase quit rates: 10.8% for no intervention, 15.1% for one format, 18.5% for 2 formats, and 23.2% for three or four formats.[12]^:91
• The transtheoretical model, including "stages of change", has been used in tailoring smoking cessation methods to individuals.[73][74][75][76] However, a 2010 Cochrane review concluded that "stage-based self-help interventions (expert systems and/or tailored materials) and individual counselling were neither more nor less effective than their non-stage-based equivalents."[77]

Some health organizations manage text messaging services to help people avoid smoking

According to the most recent Cochrane review in 2019, self-help materials may produce a small increase in quit rates specially when there is no other supporting intervention form.[78] In the 2008 Guideline, "the effect of self-help was weak", and the number of types of self-help did not produce higher abstinence rates.[12]^:89–91 Nevertheless, self-help modalities for smoking cessation include:

• In-person self-help groups such as Nicotine Anonymous,[79][80] or web-based cessation resources such as Smokefree.gov, which offers various types of assistance including self-help materials.[81]
• WebMD: a resource providing health information, tools for managing health, and support.[82]
• Interactive web-based and stand-alone computer programs and online communities which assist participants in quitting. For example, "quit meters" keep track of statistics such as how long a person has remained abstinent.[83] In the 2008 US Guideline, there was no meta-analysis of computerised interventions, but they were described as "highly promising."[12]^:93–94 A meta-analysis published in 2009,[84] a Cochrane review updated in 2017,[85] and a 2011 systematic review[86] found the evidence base for such interventions weak, although interactive and tailored interventions show some promise.
• Mobile phone-based interventions: A 2016 updated Cochrane review stated that "the current evidence supports a beneficial impact of mobile phone-based cessation interventions on six-month cessation outcomes.[87] A 2011 randomized trial of mobile phone-based smoking cessation support in the UK found that a Txt2Stop cessation program significantly improved cessation rates at 6 months.[88] A 2013 meta-analysis also noted "modest benefits" of mobile health interventions.[89]
• Interactive web-based programs combined with a Mobile phone: Two RCTs documented long-term treatment effects (abstinence rate: 20-22 %) of such interventions,.[90][91]
• Self-help books such as Allen Carr's Easy Way to Stop Smoking.[92]
• Spirituality: In one survey of adult smokers, 88% reported a history of spiritual practice or belief, and of those more than three-quarters were of the opinion that using spiritual resources may help them quit smoking.[93]
• A review of mindfulness training as a treatment for addiction showed reduction in craving and smoking following training.[94]
• Physical activities help in the maintenance of smoking cessation even if there is no conclusive evidence of the most appropriate exercise intensity.[95]

Various methods exist which allow a smoker to see the impact of their tobacco use, and the immediate effects of quitting. Using biochemical feedback methods can allow tobacco-users to be identified and assessed, and the use of monitoring throughout an effort to quit can increase motivation to quit.[96][97] A recent Cochrane Review found "little evidence about the effects of most types of biomedical tests for risk assessment on smoking cessation." [98]

• Breath carbon monoxide (CO) monitoring: Because carbon monoxide is a significant component of cigarette smoke, a breath carbon monoxide monitor can be used to detect recent cigarette use. Carbon monoxide concentration in breath has been shown to be directly correlated with the CO concentration in blood, known as percent carboxyhemoglobin. The value of demonstrating blood CO concentration to a smoker through a non-invasive breath sample is that it links the smoking habit with the physiological harm associated with smoking.[99] Within hours of quitting, CO concentrations show a noticeable decrease, and this can be encouraging for someone working to quit. Breath CO monitoring has been utilized in smoking cessation as a tool to provide patients with biomarker feedback, similar to the way in which other diagnostic tools such as the stethoscope, the blood pressure cuff, and the cholesterol test have been used by treatment professionals in medicine.[96]
• Cotinine: Cotinine, a metabolite of nicotine, is present in smokers. Like carbon monoxide, a cotinine test can serve as a reliable biomarker to determine smoking status.[100] Cotinine levels can be tested through urine, saliva, blood, or hair samples, with one of the main concerns of cotinine testing being the invasiveness of typical sampling methods.

While both measures offer high sensitivity and specificity, they differ in usage method and cost. As an example, breath CO monitoring is non-invasive, while cotinine testing relies on a bodily fluid. These two methods can be used either alone or together, for example, in a situation where abstinence verification needs additional confirmation.[101]

Financial or material incentives to entice people to quit smoking improves smoking cessation while the incentive is in place.[102] Competitions that require participants to deposit their own money, "betting" that they will succeed in their efforts to quit smoking, appear to be an effective incentive.[102] However, in head to head comparisons with other incentive models such as giving participants NRT or placing them in a more typical rewards program, it is more difficult to recruit participants for this type of contest.[103] There is evidence that incentive programs may be effective for pregnant mothers who smoke.[102]

A different 2019 Cochrane review found that there is an insufficient amount of studies on "Quit and Win" and other competition-based interventions. Results from the existing studies were inconclusive.[104]

Interventions delivered via healthcare providers and healthcare systems have been shown to improve smoking cessation among people who visit those services.

• A clinic screening system (e.g., computer prompts) to identify whether or not a person smokes doubled abstinence rates, from 3.1% to 6.4%.[12]^:78–79 Similarly, the Task Force on Community Preventive Services determined that provider reminders alone or with provider education are effective in promoting smoking cessation.[55]^:33–38
• A 2008 Guideline meta-analysis estimated that physician advice to quit smoking led to a quit rate of 10.2%, as opposed to a quit rate of 7.9% among patients who did not receive physician advice to quit smoking.[12]^:82–83 A Cochrane review found that even brief advice from physicians had "a small effect on cessation rates".[105] However, one study from Ireland involving vignettes found that physicians' probability of giving smoking cessation advice declines with the patient's age,[106] and another study from the U.S. found that only 81% of smokers age 50 or greater received advice on quitting from their physicians in the preceding year.[107]
• For one-to-one or person-to-person counselling sessions, the duration of each session, the total amount of contact time, and the number of sessions all correlated with the effectiveness of smoking cessation. For example, "Higher intensity" interventions (>10 minutes) produced a quit rate of 22.1% as opposed to 10.9% for "no contact" over 300 minutes of contact time produced a quit rate of 25.5% as opposed to 11.0% for "no minutes" and more than 8 sessions produced a quit rate of 24.7% as opposed to 12.4% for 0–1 sessions.[12]^:83–86
• Both physicians and non-physicians increased abstinence rates compared with self-help or no clinicians.[12]^:87–88 For example, a Cochrane review of 58 studies found that nursing interventions increased the likelihood of quitting.[108] Another review found some positive effects when trained community pharmacists support the customers in their smoking cessation trials.[109]
• Dental professionals also provide a key component in increasing tobacco abstinence rates in the community through counseling patients on the effects of tobacco on oral health in conjunction with an oral exam.[110]
• According to the 2008 Guideline, based on two studies the training of clinicians in smoking cessation methods may increase abstinence rates;[12]^:130 however, a Cochrane review found and measured that such training decreased smoking in patients.[111]
• Reducing or eliminating the costs of cessation therapies for smokers increased quit rates in three meta-analyses.[12]^:139–140[55]^:38–40[112]
• In one systematic review and meta-analysis, multi-component interventions increased quit rates in primary care settings.[113] "Multi-component" interventions were defined as those that combined two or more of the following strategies known as the "5 A's":[12]^:38–43
  • Ask — Systematically identify all tobacco users at every visit
  • Advise — Strongly urge all tobacco users to quit
    

    Breath CO monitor displaying carbon monoxide concentration of an exhaled breath sample (in ppm) with its corresponding percent concentration of carboxyhemoglobin.
  • Assess — Determine willingness to make a quit attempt
  • Assist — Aid the patient in quitting (provide counselling-style support and medication)
  • Arrange — Ensure follow-up contact

• Nicotine replacement therapy (NRT) is the general term for using products that contain nicotine but not tobacco to aid cessation of smoking. These include nicotine lozenges that are sucked, nicotine gum and inhalers, nicotine patches, as well as electronic cigarettes. In a review of 136 NRT-related Cochrane Tobacco Addiction Group studies, strong evidence supported NRT use in increasing the chances of successfully quitting smoking by 50 to 60% in comparison to placebo or a non-NRT control group.[114]
• Electronic cigarette: There is limited supporting evidence in helping people quit smoking.[115] The available evidence for their effectiveness in abstaining from smoking is inconclusive.[116] A 2018 review stated for people who are only willing to vape to quit smoking, they recommended that these people be told that little is known regarding the long-term harms related to vaping.[117] A 2016 UK Royal College of Physicians report supports the use of e-cigarettes as a smoking cessation tool.[118] A 2015 Public Health England report stated that "Smokers who have tried other methods of quitting without success could be encouraged to try e-cigarettes (EC) to stop smoking and stop smoking services should support smokers using EC to quit by offering them behavioural support."[119]

• Acupuncture: Acupuncture has been explored as an adjunct treatment method for smoking cessation.[120] A 2014 Cochrane review was unable to make conclusions regarding acupuncture as the evidence is poor.[121] A 2008 guideline found no difference between acupuncture and placebo, found no scientific studies supporting laser therapy based on acupuncture principles but without the needles.[12]^:99
• Chewing cinnamon sticks or gum has been recommended when trying to quit the use of tobacco.[122]
• Hypnosis: Hypnosis often involves the hypnotherapist suggesting to the patient the unpleasant outcomes of smoking.[123] Clinical trials studying hypnosis and hypnotherapy as a method for smoking cessation have been inconclusive.[12]^:100[124][125][126] A Cochrane review was unable to find evidence of benefit of hypnosis in smoking cessation, and suggested if there is a beneficial effect, it is small at best.[127] However, a randomized trial published in 2008 found that hypnosis and nicotine patches "compares favorably" with standard behavioral counseling and nicotine patches in 12-month quit rates.[128]
• Herbal medicine: Many herbs have been studied as a method for smoking cessation, including lobelia and St John's wort.[129][130] The results are inconclusive, but St. Johns Wort shows few adverse events. Lobelia has been used to treat respiratory diseases like asthma and bronchitis, and has been used for smoking cessation because of chemical similarities to tobacco; lobelia is now listed in the FDA's Poisonous Plant Database.[131] Lobelia can still be found in many products sold for smoking cessation and should be used with caution.
• Smokeless tobacco: There is little smoking in Sweden, which is reflected in the very low cancer rates for Swedish men. Use of snus (a form of steam-pasteurized, rather than heat-pasteurized, air-cured smokeless tobacco) is an observed cessation method for Swedish men and even recommended by some Swedish doctors.[132] However, the report by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) concludes "STP (smokeless tobacco products) are addictive and their use is hazardous to health. Evidence on the effectiveness of STP as a smoking cessation aid is insufficient."[133] A recent national study on the use of alternative tobacco products, including snus, did not show that these products promote cessation.[134]
• Aversion therapy: It is a method of treatment works by pairing the pleasurable stimulus of smoking with other unpleasant stimuli. A Cochrane review reported that there is insufficient evidence of its efficacy.[135]
• Nicotine vaccines: Nicotine vaccines (e.g., NicVAX and TA-NIC) work by reducing the amount of nicotine reaching the brain; however, this method of therapy needs more investigations to establish its role and determine its side effects.[136]
• Technology and machine learning: Research studies using machine learning or artificial intelligence tools to provide feedback and communication with those who are trying to quit smoking are increasing, yet the findings are so far inconclusive.[137][138][139]

The burden of tobacco-related disease such as tobacco-related cancers, heart disease and stroke is greater for African Americans than for European Americans.[141] Among ever smokers, 51% of European Americans but only 37% of African Americans had quit and among former smokers African Americans continued smoking for longer periods before quitting and age at quitting was older compared to European Americans.[142] Hence, the need for culturally-specific smoking cessation treatment.

Methods used with children and adolescents include:

• Motivational enhancement[143]
• Psychological support[143]
• Youth anti-tobacco activities, such as sport involvement
• School-based curricula, such as life-skills training
• School-based nurse counseling sessions[144]
• Access reduction to tobacco
• Anti-tobacco media[145][146]
• Family communication

Cochrane reviews, mainly of studies combining motivational enhancement and psychological support, concluded that "complex approaches" for smoking cessation among young people show promise.[143][147] The 2008 US Guideline recommends counselling-style support for adolescent smokers on the basis of a meta-analysis of seven studies.[12]^:159–161 Neither the Cochrane review nor the 2008 Guideline recommends medications for adolescents who smoke.

Smoking during pregnancy can cause adverse health effects in both the woman and the fetus. The 2008 US Guideline determined that "person-to-person psychosocial interventions" (typically including "intensive counseling") increased abstinence rates in pregnant women who smoke to 13.3%, compared with 7.6% in usual care.[12]^:165–167 Mothers who smoke during pregnancy have a greater tendency towards premature births. Their babies are often underdeveloped, have smaller organs, and weigh much less than the normal baby. In addition, these babies have weaker immune systems, making them more susceptible to many diseases such as middle ear inflammations and asthmatic bronchitis as well as metabolic conditions such as diabetes and hypertension, all of which can bring significant morbidity.[148] Additionally, a study published by American Academy of Pediatrics shows that smoking during pregnancy increases the chance of sudden unexpected infant death (SUID).[149] There is also an increased chance that the child will be a smoker in adulthood. A systematic review showed that psychosocial interventions help women to stop smoking in late pregnancy and can reduce the incidence of low birthweight infants.[150]

It is a myth that a female smoker can cause harm to a fetus by quitting immediately upon discovering she is pregnant. This idea is not based on any medical study or fact.[151]

Studies across 20 countries show a strong association between patients with schizophrenia and smoking. People with schizophrenia are much more likely to smoke than those without the disease.[152] For example, in the United States, 80% or more of people with schizophrenia smoke, compared to 20% of the general population in 2006.[153]

A 2008 Cochrane review of smoking cessation activities in work-places concluded that "interventions directed towards individual smokers increase the likelihood of quitting smoking".[154] A 2010 systematic review determined that worksite incentives and competitions needed to be combined with additional interventions to produce significant increases in smoking cessation rates.[155]

Percent increase of success for six months over unaided attempts for each type of quitting (chart from West & Shiffman based on Cochrane review data[156]^:59

Smokers who are hospitalised may be particularly motivated to quit.[12]^:149–150 A 2012 Cochrane review found that interventions beginning during a hospital stay and continuing for one month or more after discharge were effective in producing abstinence.[157]

Patients undergoing elective surgery may get benefits of preoperative smoking cessation interventions, when starting 4–8 weeks before surgery with weekly counseling intervention for behavioral support and use of nicotine replacement therapy.[158] It is found to reduce the complications and the number of postoperative morbidity.[158]

People who have mood disorders or attention deficit hyperactivity disorders have a greater chance to begin smoking and lower chance to quit smoking.[159] A higher correlation with smoking has also been seen in people diagnosed with major depressive disorder at any time throughout the duration of their lifetime as compared to those without the diagnosis. Success rates in quitting smoking were lower for those with a major depressive disorder diagnosis versus people without the diagnosis.[160] Exposure of cigarette smoke early on in life during pregnancy, infancy, or adolescence may negatively impact a child's neurodevelopment and increase the risk of developing anxiety disorders in the future.[161]

Homelessness doubles the likelihood of an individual currently being a smoker. This is independent of other socioeconomic factors and behavioral health conditions. Homeless individuals have the same rates of the desire to quit smoking but are less likely than the general population to be successful in their attempt to quit.[162][163]

In the United States, 60-80% of homeless adults are current smokers. This is a considerably higher rate than that of the general adult population of 19%.[162] Many current smokers who are homeless report smoking as a means of coping with "all the pressure of being homeless."[162] The perception that homeless people smoking is "socially acceptable" can also reinforce these trends.[162]

Americans under the poverty line have higher rates of smoking and lower rates of quitting than those over the poverty line.[163][164][165] While the homeless population as a whole is concerned about short-term effects of smoking, such as shortness of breath of recurrent bronchitis, they are not as concerned with long-term consequences.[164] The homeless population has unique barriers to quit smoking such as unstructured days, the stress of finding a job, and immediate survival needs that supersede the desire to quit smoking.[164]

These unique barriers can be combated through pharmacotherapy and behavioral counseling for high levels of nicotine dependence, emphasis of immediate financial benefits to those who concern themselves with the short-term over the long-term, partnering with shelters to reduce the social acceptability of smoking in this population, and increased taxes on cigarettes and on alternative tobacco products to further make the addiction more difficult to fund.[166]

Smoking is very common among people living with HIV/AIDS and it impacts morbidity and mortality substantially. Combined smoking cessation interventions provide good long-term control.[167]

Over three-quarters of people in treatment for substance use are current smokers.[168] Providing counseling and pharmacotherapy (nicotine replacement therapy such as patches or gum, varenicline, and/or bupropion) increases tobacco abstinence without increasing the risk of returning to other substance use.[169]

In a 2007 review of the effects of abstinence from tobacco, Hughes concluded that "anger, anxiety, depression, difficulty concentrating, impatience, insomnia, and restlessness are valid withdrawal symptoms that peak within the first week and last 2–4 weeks."[185] In contrast, "constipation, cough, dizziness, increased dreaming, and mouth ulcers" may or may not be symptoms of withdrawal, while drowsiness, fatigue, and certain physical symptoms ("dry mouth, flu symptoms, headaches, heart racing, skin rash, sweating, tremor") were not symptoms of withdrawal.[185]

Giving up smoking is associated with an average weight gain of 4–5 kilograms (8.8–11.0 lb) after 12 months, most of which occurs within the first three months of quitting.[186]

The possible causes of the weight gain include:

• Smoking over-expresses the gene AZGP1 which stimulates lipolysis, so smoking cessation may decrease lipolysis.[187]
• Smoking suppresses appetite, which may be caused by nicotine's effect on central autonomic neurons (e.g., via regulation of melanin concentrating hormone neurons in the hypothalamus).[188]
• Heavy smokers are reported to burn 200 calories per day more than non-smokers eating the same diet.[189] Possible reasons for this phenomenon include nicotine's ability to increase energy metabolism or nicotine's effect on peripheral neurons.[188]

The 2008 Guideline suggests that sustained-release bupropion, nicotine gum, and nicotine lozenge be used "to delay weight gain after quitting."[12]^:173–176 A 2012 Cochrane review concluded that there is not sufficient evidence to recommend a particular program for preventing weight gain.[190]

Like other physically addictive drugs, nicotine addiction causes a down-regulation of the production of dopamine and other stimulatory neurotransmitters as the brain attempts to compensate for the artificial stimulation caused by smoking. Therefore, when people stop smoking, depressive symptoms such as suicidal tendencies or actual depression may result,[178][191] although a recent international study comparing smokers who had stopped for 3 months with continuing smokers found that stopping smoking did not appear to increase anxiety or depression.[192] This side effect of smoking cessation may be particularly common in women, as depression is more common among women than among men.[193]

A recent study by The British Journal of Psychiatry has found that smokers who successfully quit feel less anxious afterward with the effect being greater among those who had mood and anxiety disorders than those that smoked for pleasure.[194]