In simple terms, quitting smoking has two major components: making an attempt to quit, and maintaining abstinence. These two tasks do not necessarily have the same predictors. 1 For example, motivational factors are very important in prompting an attempt to quit, whereas a person’s level of nicotine dependence is the most important predictor of his or her ability to maintain abstinence. 2
7.6.1 Planned versus spontaneous
Tobacco dependence guidelines for health professionals traditionally promoted the idea of planning quit attempts in advance; 3, 4 however more recent guidelines acknowledge that quit attempts made with minimal planning can be successful. 5 Reported planning may be more likely among those who are more addicted, and those who plan may be more likely to use a quit aid, particularly pharmacotherapy. 6 Among those who do set a quit date, choosing a date sooner rather than later appears to lead to greater long-term success. 7, 8 However, unplanned or spontaneous quit attempts are common and they can also be a successful route to cessation. 6, 9-11 Some findings suggest that spontaneous attempts may have a greater chance of long-term success than those that are planned. 12 The International Tobacco Control Four Country Survey (ITC-4) found no evidence of a benefit of planning either before or after the initiation of a quit attempt on short-term success. 13
However, discussion about planned versus unplanned attempts is complicated by the difficulty in clearly distinguishing between the two approaches. Reported unplanned attempts can often involve elements of planning, such as first accessing cessation support. 14, 15 In the ITC-4 study, more than half of those who reported a spontaneous quit attempt (i.e., those who stopped smoking immediately upon deciding to quit) also reported some pre-quit planning. 13 These findings suggest the need for a greater focus on the changeable nature of motivation, and the importance of recognising that it is often opportunistic or abrupt. 9 (See Section 7.3 for theories about smoking and quitting). Smoking cessation services might offer flexible and adaptable support that can be used readily by potential quitters. 15
7.6.2 Abrupt versus gradual
Common methods of quitting involve either abruptly stopping smoking (‘going cold turkey’) or gradually reducing the number of cigarettes smoked per day before stopping completely (‘cutting down to quit’). When cutting down, the number of cigarettes per day may be reduced in a scheduled or unscheduled way, or the first cigarette of the day is delayed for longer and longer. Cold turkey is a more commonly used strategy than cutting down among smokers trying to quit. 16-18
Surveys carried out in the general population have found that going cold turkey is more effective than cutting down. 16, 19, 20 This may be due to smokers who choose reduction being more addicted, less motivated to quit, or differing in other important ways to those who quit cold turkey. 16, 21-24 A 2019 Cochrane review of randomised controlled trials comparing the efficacy of abrupt versus gradual cessation concluded that cutting down before quitting may result in similar quit rates to quitting cold turkey, therefore smokers’ preferences should be considered when providing cessation advice and support. 25
Encouraging some smokers in their efforts in cutting down prior to a future quit attempt may increase population-level cessation rates. 21 Some smokers prefer cutting down, particularly if their attempts to abruptly quit have previously failed. 23 For smokers unwilling to quit, or for those unwilling to quit abruptly, smoking reduction approaches using pharmacotherapy alone or combined with behavioural interventions may significantly increase eventual successful cessation. 26-29 The 2019 Cochrane review found that for those who choose to cut down, using fast‐acting NRT or varenicline alongside smoking reduction may help to increase the success of quit attempts. 25 NRT-assisted reduction appears to be an effective intervention for achieving sustained smoking abstinence for smokers unwilling or unable to quit, 27, 30-32 and is effective and cost effective compared to no quit attempt. 33 (Note that the addition of NRT also increases the success of abrupt quit attempts—See Section 7.16). 33
One review also found that a greater reduction in cigarettes per day predicted a greater probability of cessation (i.e., there appears to be a dose–response relationship between cutting down and cessation success). 34 Further evidence is needed to examine whether other methods of reduction, such as cutting out certain cigarettes or smoking to particular schedules, are more effective than others. 35 It is important to note that the primary benefit of cutting down is as a step toward complete cessation. Low intensity (‘light’) smoking or occasional (‘social’) smoking do not meaningfully reduce smokers’ risks of disease or death—see Section 18.3.
7.6.3 Unassisted versus assisted
Behavioural counselling and pharmacotherapies can improve the likelihood that a quit attempt is successful, however most people who quit do so without the use of quitting aids and professional support even when such support is available. 36-44 The large numbers of smokers who have quit using this method means that unassisted quitting has been a major contributor to the reduction in smoking prevalence. 45, 46
Smokers who perceive quitting aids as helpful are more likely to try to quit and to use assistance. 47 There is some international evidence that being older, female, more nicotine dependent, more educated, and wealthier is related to use of assistance to quit. 48-50 Survey data from New South Wales shows that (prior to subsidisation of nicotine replacement therapy on the Pharmaceutical Benefits Scheme) receiving health professional advice and use of nicotine replacement therapy, natural therapy and prescribed medication were higher among older smokers and those from low socio-economic groups, while use of the Quitline was higher among the middle age group. 17 Conversely, a Danish study found that quitting unaided was more likely among men, younger age groups, those with a shorter history of smoking and those who were light smokers. 51 Research in the EU found that smokers living in countries with comprehensive tobacco cessation programmes that offered cost-covered national quit lines, medication, and other cessation services were more likely to use effective cessation aids, highlighting the importance of access to cessation assistance as part of a comprehensive tobacco control program. 52 Individual smokers may also switch between assisted and unassisted attempts over the course of trying to quit smoking. 53
A 2015 review of the qualitative literature on smokers who quit unassisted explored the views and experiences of such smokers. Three key concepts were identified—motivation, willpower, and commitment—as important to smokers and ex-smokers who quit without formal assistance. The authors conclude that having a better understanding of this strategy, which is employed by the vast majority of smokers who quit, can inform more nuanced and effective communication and cessation support. 54 Australian community research has found that smokers’ reasons for quitting unassisted are complex and go beyond issues relating to misperceptions or treatment barriers. Smokers reported prioritising lay knowledge; evaluating the costs and benefits of quitting options; believing quitting is their personal responsibility; and perceiving quitting unassisted to be the right or better option. 55 Another Australian study similarly found that smokers often described unassisted quitting as the best method, and expressed negative attitudes toward pharmacotherapies, particularly concerns about side effects from prescription medications. 56 These results may also help shape effective guidance by health professionals, who could validate unassisted quitting when it is preferred by smokers and modify brief interventions as appropriate. 55
Use of quitting medications and support services has become more common over the past decade, 36, 52, 57, 58 especially among more dependent smokers. A survey of Australian smokers from 2002 to 2009 found that use of prescription medication to quit smoking increased over time, particularly after the addition of varenicline to the Pharmaceutical Benefits Scheme in 2008. Among smokers who tried to quit, use of help rose gradually from 37% in 2002 to almost 59% in 2009 (including 52% using pharmacotherapy and 15% using behavioural forms of support). 59
The 2019 National Drug Strategy Household Survey asked smokers about any cessation strategies they might have used, and respondents were able to choose multiple responses. Among smokers aged 18 and over who had tried to quit in the previous year (successfully or unsuccessfully), 3% had contacted the Quitline, 14% had asked their doctor for help to quit, and 23% had used nicotine gum, patches, spray or inhalers. Ten per cent reported using a smoking cessation pill. Other responses included using e-cigarettes to cut down (16%) or to quit (12%), some other type of product (9%), reading cessation literature in a brochure or on the internet (10%), or using a mobile phone app (9%). Going cold turkey was the most popular approach, with more than one in three quit attempters (35%) adopting this strategy. 60
It is important to note that population-based or ‘real-world’ studies have highlighted the importance of smokers utilising best-practice cessation support; i.e., pharmacotherapies combined with behavioural support, to increase their odds of successful cessation. Smokers who use NRT purchased over the counter with no behavioural support appear no more likely to successfully quit than those who do so unassisted. 61-63 In Australia, a condition for the PBS-subsidy of smoking cessation medications is that the smoker participates in cessation counselling, with evidence showing this combination provides smokers with the greatest chance of achieving long-term cessation. 64
Relevant news and research
For recent news items and research on this topic, click here. ( Last updated December 2024)
References
1. Vangeli E, Stapleton J, Smit ES, Borland R, and West R. Predictors of attempts to stop smoking and their success in adult general population samples: a systematic review. Addiction, 2011; 106(12):2110–21. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21752135
2. Hyland A, Borland R, Li Q, Yong HH, McNeill A, et al. Individual-level predictors of cessation behaviours among participants in the International Tobacco Control (ITC) Four Country Survey. Tobacco Control, 2006; 15 Suppl 3(suppl. 3):iii83–94. Available from: https://www.ncbi.nlm.nih.gov/pubmed/16754952
3. Fiore M, Bailey W, and Cohen S, et al. Treating tobacco use and dependence. Clinical practice guideline. Rockville MD: US Department of Health and Human Services. Public Health Service., 2000. Available from: https://pubmed.ncbi.nlm.nih.gov/11054899/
4. Abrams D, Niaura R, and Brown R, The tobacco dependence treatment handbook. A Guide to best practices. New York: Guilford; 2003. Available from: http://www.books-by-isbn.com/1-57230/1572308494-The-Tobacco-Dependence-Treatment-Handbook-A-Guide-to-Best-Practices-1-57230-849-4.html.
5. The Royal Australian College of General Practitioners, Supporting smoking cessation: a guide for health professionals. Melbourne: RACGP; 2014. Available from: http://www.racgp.org.au/your-practice/guidelines/smoking-cessation/.
6. Sendzik T, McDonald PW, Brown KS, Hammond D, and Ferrence R. Planned quit attempts among Ontario smokers: impact on abstinence. Addiction, 2011; 106(11):2005–13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21592249
7. Anesi GL, Halpern SD, Harhay MO, Volpp KG, and Saulsgiver K. Time to selected quit date and subsequent rates of sustained smoking abstinence. Journal of Behavioral Medicine, 2017; 40(6):989–97. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28639106
8. Zawertailo L, Ragusila A, Voci S, Ivanova A, Baliunas D, et al. Target quit date timing as a predictor of smoking cessation outcomes. Psychology of Addictive Behaviors, 2017; 31(6):655–63. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28703612
9. Larabie LC. To what extent do smokers plan quit attempts? Tobacco Control, 2005; 14(6):425–8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/16319368
10. West R and Sohal T. "Catastrophic" pathways to smoking cessation: findings from national survey. BMJ, 2006; 332(7539):458–60. Available from: https://www.ncbi.nlm.nih.gov/pubmed/16443610
11. Ferguson SG, Shiffman S, Gitchell JG, Sembower MA, and West R. Unplanned quit attempts--results from a U.S. sample of smokers and ex-smokers. Nicotine and Tobacco Research, 2009; 11(7):827–32. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19509277
12. Toftgård M, Gilljam H, and Tomson T. Pathways to smoking and snus use cessation: is spontaneous quitting underrated? The Open Epidemiology Journal, 2010; 3:20–3. Available from: http://bentham.org/open/toepij/articles/V003/20TOEPIJ.pdf
13. Balmford J, Swift E, and Borland R. Reported planning before and after quitting and quit success: retrospective data from the ITC 4-Country Survey. Psychology of Addictive Behaviors, 2014; 28(3):899–906. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25134049
14. Smith AL, Carter SM, Dunlop SM, Freeman B, and Chapman S. Measured, opportunistic, unexpected and naive quitting: a qualitative grounded theory study of the process of quitting from the ex-smokers' perspective. BMC Public Health, 2017; 17(1):430. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28490317
15. Murray RL, McNeill A, Lewis S, Britton J, and Coleman T. Unplanned attempts to quit smoking: a qualitative exploration. Addiction, 2010; 105(7):1299–302. Available from: https://www.ncbi.nlm.nih.gov/pubmed/20642512
16. Cheong Y, Yong H-H, and Borland R. Does how you quit affect success? A comparison between abrupt and gradual methods using data from the International Tobacco Control Policy Evaluation Study. Nicotine and Tobacco Research, 2007; 9(8):801–10. Available from: https://pubmed.ncbi.nlm.nih.gov/17654293/
17. Hung WT, Dunlop SM, Perez D, and Cotter T. Use and perceived helpfulness of smoking cessation methods: results from a population survey of recent quitters. BMC Public Health, 2011; 11(1):592. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21791111
18. Caraballo RS, Shafer PR, Patel D, Davis KC, and McAfee TA. Quit methods used by US adult cigarette smokers, 2014-2016. Preventing Chronic Disease, 2017; 14:E32. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28409740
19. West R, McEwen A, Bolling K, and Owen L. Smoking cessation and smoking patterns in the general population: a 1-year follow-up. Addiction, 2001; 96(6):891–902. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11399220
20. Garnett C, Brown J, Shahab L, Raupach T, and Lindson N. Potential explanations for conflicting findings on abrupt versus gradual smoking cessation: A population study in England. Nicotine and Tobacco Research, 2022; 24(4):574–80. Available from: https://www.ncbi.nlm.nih.gov/pubmed/34792598
21. Lindson-Hawley N, Banting M, West R, Michie S, Shinkins B, et al. Gradual versus abrupt smoking cessation: A randomized, controlled noninferiority trial. Annals of Internal Medicine, 2016; 164(9):585–92. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26975007
22. Lindson N, Klemperer EM, and Aveyard P. Is there a place for cutting-down-to-stop in smoking cessation support? Addiction, 2020; 115(10):1797–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31845439
23. Etter JF. Comparing abrupt and gradual smoking cessation: a randomized trial. Drug and Alcohol Dependence, 2011; 118(2-3):360–5. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21571448
24. Petersen A, Mermelstein R, Berg KM, Baker TB, Smith SS, et al. Offering smoking treatment to primary care patients in two Wisconsin healthcare systems: Who chooses smoking reduction versus cessation? Preventive Medicine, 2017; 105:332–6. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28988997
25. Lindson N, Klemperer E, Hong B, Ordonez-Mena JM, and Aveyard P. Smoking reduction interventions for smoking cessation. Cochrane Database of Systematic Reviews, 2019; 9:CD013183. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31565800
26. Asfar T, Ebbert JO, Klesges RC, and Relyea GE. Do smoking reduction interventions promote cessation in smokers not ready to quit? Addictive Behaviors, 2011; 36(7):764–8. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21420791
27. Moore D, Aveyard P, Connock M, Wang D, Fry-Smith A, et al. Effectiveness and safety of nicotine replacement therapy assisted reduction to stop smoking: systematic review and meta-analysis. BMJ, 2009; 338:b1024. Available from: https://www.ncbi.nlm.nih.gov/pubmed/19342408
28. Etter JF and Laszlo E. Postintervention effect of nicotine replacement therapy for smoking reduction: a randomized trial with a 5-year follow-up. Journal of Clinical Psychopharmacology, 2007; 27(2):151–5. Available from: https://www.ncbi.nlm.nih.gov/pubmed/17414237
29. Nakamura M, Abe M, Ohkura M, Treadow J, Yu CR, et al. Efficacy of varenicline for cigarette reduction before quitting in Japanese smokers: A subpopulation analysis of the reduce to quit trial. Clinical Therapeutics, 2017; 39(4):863–72. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28365035
30. Stead LF and Lancaster T Interventions to reduce harm from continued tobacco use. Cochrane Database of Systematic Reviews, 2007 DOI: 10.1002/14651858.CD005231.pub2. Available from: http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD005231/frame.html
31. Begh R, Lindson-Hawley N, and Aveyard P. Does reduced smoking if you can't stop make any difference? BMC Medicine, 2015; 13:257. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26456865
32. Engle JL, Mermelstein R, Baker TB, Smith SS, Schlam TR, et al. Effects of motivation phase intervention components on quit attempts in smokers unwilling to quit: A factorial experiment. Drug and Alcohol Dependence, 2019; 197:149–57. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30825795
33. Wang D, Connock M, Barton P, Fry-Smith A, Aveyard P, et al. 'Cut down to quit' with nicotine replacement therapies in smoking cessation: a systematic review of effectiveness and economic analysis. Health Technology Assessment, 2008; 12(2):1–135. Available from: http://www.ncbi.nlm.nih.gov/pubmed/18093448
34. Klemperer EM and Hughes JR. Does the magnitude of reduction in cigarettes per day predict smoking cessation? A qualitative review. Nicotine and Tobacco Research, 2016; 18(1):88–92. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25744970
35. Lindson N, Michie S, and Aveyard P. Exploratory analyses of the popularity and efficacy of four behavioral methods of gradual smoking cessation. Nicotine and Tobacco Research, 2020; 22(12):2257–61. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32609847
36. Chapman S. Accelerating smoking cessation and prevention in whole communities, in Public Health Advocacy and Tobacco Control: Making Smoking History. Blackwell Publishing; 2007. Available from: https://catalogue.nla.gov.au/Record/4935337.
37. Yeomans K, Payne KA, Marton JP, Merikle EP, Proskorovsky I, et al. Smoking, smoking cessation and smoking relapse patterns: a web-based survey of current and former smokers in the US. International Journal of Clinical Practice, 2011; 65(10):1043–54. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21923845
38. Edwards SA, Bondy SJ, Callaghan RC, and Mann RE. Prevalence of unassisted quit attempts in population-based studies: a systematic review of the literature. Addictive Behaviors, 2014; 39(3):512–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24333037
39. Kotz D, Batra A, and Kastaun S. Smoking cessation attempts and common strategies employed. Dtsch Arztebl Int, 2020; 117(1-2):7–13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32008606
40. Jiang S, Yang T, Bullen C, Chen J, Yu L, et al. Real-world unassisted quit success and related contextual factors: a population-based study of Chinese male smokers. Tobacco Control, 2021; 30(5):498–504. Available from: https://www.ncbi.nlm.nih.gov/pubmed/32675250
41. Manis M, Tamm M, and Stolz D. Unaided smoking cessation in healthy employees. Respiration, 2018; 95(2):80–6. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29131057
42. Soulakova JN and Crockett LJ. Unassisted Quitting And Smoking Cessation Methods Used In The United States: Analyses of 2010-2011 Tobacco Use Supplement to the Current Population Survey Data. Nicotine and Tobacco Research, 2017; 20(1):30–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/27798084
43. Ahluwalia IB, Tripp AL, Dean AK, Mbulo L, Arrazola RA, et al. Tobacco smoking cessation and quitline use among adults aged >/=15 years in 31 countries: Findings from the Global Adult Tobacco Survey. American Journal of Preventive Medicine, 2021; 60(3 Suppl 2):S128–S35. Available from: https://www.ncbi.nlm.nih.gov/pubmed/33663700
44. El Asmar ML, Laverty AA, Vardavas CI, and Filippidis FT. How do Europeans quit using tobacco, e-cigarettes and heated tobacco products? A cross-sectional analysis in 28 European countries. BMJ Open, 2022; 12(4):e059068. Available from: https://www.ncbi.nlm.nih.gov/pubmed/35487758
45. Smith AL and Chapman S. Quitting smoking unassisted: the 50-year research neglect of a major public health phenomenon. JAMA, 2014; 311(2):137–8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24399549
46. Chapman S, Quit Smoking Weapons of Mass Distraction. Sydney University Press; 2022. Available from: https://ses.library.usyd.edu.au/handle/2123/28576.
47. Hammond D, McDonald P, Fong G, and Borland R. Do smokers know how to quit? Knowledge and perceived effectiveness of cessation assistance as predictors of cessation behaviour. Addiction, 2004; 99(8):1042–8. Available from: https://pubmed.ncbi.nlm.nih.gov/15265101/
48. Shiffman S, Brockwell SE, Pillitteri JL, and Gitchell JG. Use of smoking-cessation treatments in the United States. American Journal of Preventive Medicine, 2008; 34(2):102–11. Available from: http://www.sciencedirect.com/science/journal/07493797
49. Shiffman S, Brockwell SE, Pillitteri JL, and Gitchell JG. Individual differences in adoption of treatment for smoking cessation: demographic and smoking history characteristics. Drug and Alcohol Dependence, 2008; 93(1-2):121–31. Available from: https://www.ncbi.nlm.nih.gov/pubmed/17996399
50. McCarthy M, Siahpush M, Shaikh RA, Sikora Kessler A, and Tibbits M. Social disparities in unaided quit attempts among daily current and former smokers: Results from the 2010-2011 Tobacco Use Supplement to the Current Population Survey. Nicotine and Tobacco Research, 2016; 18(8):1705–10. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26764257
51. Mikkelsen SS, Dalum P, Skov-Ettrup LS, and Tolstrup JS. What characterises smokers who quit without using help? A study of users and non-users of cessation support among successful ex-smokers. Tobacco Control, 2015; 24(6):556–61. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24935443
52. Filippidis FT, Gerovasili V, Vardavas CI, Agaku IT, and Tountas Y. Determinants of use of smoking cessation aids in 27 European countries. Preventive Medicine, 2014; 65:99–102. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24832820
53. Smith AL, Carter SM, Dunlop SM, Freeman B, and Chapman S. Revealing the complexity of quitting smoking: a qualitative grounded theory study of the natural history of quitting in Australian ex-smokers. Tobacco Control, 2018; 27(5):568–76. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29170168
54. Smith AL, Carter SM, Dunlop SM, Freeman B, and Chapman S. The views and experiences of smokers who quit smoking unassisted. A systematic review of the qualitative evidence. PLoS ONE, 2015; 10(5):e0127144. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26010369
55. Smith AL, Carter SM, Chapman S, Dunlop SM, and Freeman B. Why do smokers try to quit without medication or counselling? A qualitative study with ex-smokers. BMJ Open, 2015; 5(4):e007301. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25933811
56. Morphett K, Partridge B, Gartner C, Carter A, and Hall W. Why don't smokers want help to quit? A qualitative study of smokers' attitudes towards assisted vs. Unassisted quitting. International Journal of Environmental Research and Public Health, 2015; 12(6):6591–607. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26068089
57. Chapman S, Relapse and other realities: an update on smoking cessation rates in Australia. SmithKline Beecham; (World No Tobacco Day) 2000.
58. Brennan E, Durkin S, Wakefield M, and Dunlop S. Victorian current and former smokers’ quitting activity and the impact of cessation aids, services and anti-smoking campaigns. CBRC Research Paper Series, No. 29. Melbourne: Centre for Behavioural Research in Cancer, The Cancer Council Victoria, 2007.
59. Cooper J, Borland R, and Yong HH. Australian smokers increasingly use help to quit, but number of attempts remains stable: findings from the International Tobacco Control Study 2002-09. Australian and New Zealand Journal of Public Health, 2011; 35(4):368–76. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21806733
60. Australian Institute of Health and Welfare. National Drug Strategy Household Survey, 2019. ADA Dataverse, 2021. Available from: http://dx.doi.org/10.26193/WRHDUL.
61. Kotz D, Brown J, and West R. 'Real-world' effectiveness of smoking cessation treatments: a population study. Addiction, 2014; 109(3):491–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24372901
62. Kotz D, Brown J, and West R. Prospective cohort study of the effectiveness of smoking cessation treatments used in the "real world". Mayo Clinic Proceedings, 2014; 89(10):1360–7. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25282429
63. Jackson SE, Kock L, Kotz D, and Brown J. Real-world effectiveness of smoking cessation aids: A population survey in England with 12-month follow-up, 2015-2020. Addictive Behaviors, 2022; 135:107442. Available from: https://www.ncbi.nlm.nih.gov/pubmed/35908322
64. US Department of Health and Human Services. Smoking Cessation. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, 2020. Available from: https://www.hhs.gov/sites/default/files/2020-cessation-sgr-full-report.pdf