Category Archives: Literature research

Do Smokers Consist of a Single Group?

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When you think of a smoker, it is likely that you are imagining someone who goes through a pack of cigarettes per day and can often be found running to the nearest store to maintain their supply. Perhaps you amuse yourself watching your friend conspicuously leaving work to stand outside and huddle around their cigarette in the rain. Your assumption would often be correct as the majority of smokers are dependent on nicotine and smoke throughout the day. These daily smokers account for approximately 89% of current smokers in the UK (Herbec, Brown and West 2014), and between 67%-75% of smokers in the USA (Coggins, Murrelle and Carchman 2009). However, what about this missing proportion of smokers?

This consists of non-daily smokers, a sub-group of smokers who only consume a few cigarettes per day and can often engage in voluntary days of abstinence without experiencing the effects of withdrawal (Shiffman, Ferguson and Dunbar 2012b). What makes these smokers interesting is that although they do not appear to be dependent on nicotine, 82% of them relapse within 90 days of attempting to quit (Tindle and Shiffman 2011). Compared to 87% of daily smokers, these figures are remarkably close. Similar results were found in a UK sample as 92% of daily smokers and 83% of non-daily smokers failed to remain abstinent beyond six months (Herbec et al. 2014). Despite this difficulty, smoking cessation therapies lack efficacy in non-daily smokers due to a reliance on nicotine replacement therapy (Jimenéz-Ruiz and Fagerström 2010). This is not surprising as clinical trials commonly exclude light smokers (Shiffman 2009), and they rarely experience withdrawal symptoms due to a lack of nicotine dependence.

As smoking restrictions become more and more stringent, the proportion of light smokers is predicted to increase (Coggins et al. 2009; Shiffman 2009). Although light smoking is often perceived as being less harmful, it is associated with the same increased risk of developing cardiovascular disease, lung and other types of cancer as heavy smoking. For example, one prospective study found that male and female light smokers had a significantly increased risk of ischaemic heart disease and lung cancer in comparison to non-smokers (Bjartveit and Tverdal 2005). Furthermore, a systematic review found that light smokers show an intermediate risk between non-smokers and heavy smokers, but interestingly they share the same risk for heart disease as heavy smokers (Schane, Ling and Glantz 2009). Considering this, it is important to understand what the differences are between the groups, and how we can identify them.    

What are the differences in smoking patterns?

Table 1 shows the number of cigarettes smoked per day by light and heavy smokers in a small range of studies that include figures for both groups. Although there is some fluctuation, smoking rates are approximately 15 and 4 cigarettes per day for heavy and light smokers respectively. Additionally, it is interesting that light smokers often engage in voluntary days of abstinence. Compared to heavy smokers who consistently use cigarettes every day, one study found that light smokers only tend to use cigarettes on only four days per week (Shiffman, Tindle and Li 2013). This suggests that light smokers are relatively free of nicotine dependence as the half-life of nicotine in the body is approximately two hours (Advokat, Comaty and Julien 2014). This is usually the time heavy smokers start to crave their next cigarette, but it appears that light smokers are comfortable without smoking for hours and even days after all of the nicotine has been metabolised and left the body.

Table 1

Mean Number of Cigarettes Smoked Per Day in Light and Heavy smokers

Study Smoking Group Cigarettes Per Day
Herbec et al. (2014) Daily

Non-Daily

13.90

5.20

Shiffman et al. (2012a) Daily

Intermittent

15.00

4.50

Shiffman, Dunbar and Benowitz (2014a) Daily

Intermittent

15.98

3.24

Shiffman et al. (2014b) Daily

Intermittent

15.01

4.45

Scheuermann et al. (2015) Moderate Daily

Light Daily

Converted Non-Daily

Native Non-Daily

20.60

7.41

5.78

4.25

Note: Smoking group names are reproduced with those used within each study

The early dismissal of non-daily smokers was based on the belief that they only consisted of adolescents who were in a transitioning state on the way to being a heavy smoker (Shiffman 2009). Whilst this does not provide a full explanation, non-daily smoking as a young adult is indeed an important risk factor for becoming a daily smoker later in life. One cohort study found that non-daily smoking at age 21 was associated with an odds ratio of 3.60 to becoming a daily smoker at age 38 upon follow-up (Robertson, Losua and McGee 2015). In terms of public health, this highlights the need for research to focus on non-daily adolescent smokers as they could be the target of interventions before they progress into heavier, daily smoking. However, it is not only a transient state on the road to becoming a heavy smoker. The non-daily smokers in Shiffman et al. (2012b) had been smoking for an average of 18 years, and those in Shiffman et al. (2013) had smoked an estimated 42,000 cigarettes. This suggests that light, non-daily smoking can also be a consistent behaviour pattern that can last throughout adulthood.

What are the reasons people report for smoking?

Non-daily smokers appear to show markedly different smoking habits, but they also show large differences in their reported reasons for smoking. The dominant paradigm of addictive behaviour for smokers centred around continuing to use cigarettes to avoid experiencing the aversive effects of withdrawal (Shiffman 2009). This motive appears to be consistent with heavy smokers as they cite cravings, tolerance, and a loss of control over cigarette availability as influences to smoke (Shiffman et al. 2012a). This is also consistent in young heavy smokers as higher scores of nicotine dependence was associated with smoking due to craving and habit in a sample of college students (Piasecki, Richardson and Smith 2007).

On the other hand, non-daily smokers report to smoke for radically different reasons. For example, exposure to smoking cues, weight control, sensory experiences of smoking, and positive reinforcement have been cited as motives for non-daily smokers (Shiffman et al. 2012a). This is inconsistent with daily smokers as rather than avoiding the negative experiences of smoking, they appear to smoke for the positive experiences. This has led non-daily smokers to be labelled as ‘indulgent’, as they tend to smoke to enhance the experience of situations that are already positive such as drinking alcohol in a bar with friends (Shiffman, Dunbar and Li 2014). As well as showing different habits and smoking patterns, non-daily smokers report being motivated to smoke by substantially different reasons to those normally proposed in daily smokers.

 

How can you measure cigarette consumption?

Definitions of light and heavy smoking

You may have noticed that a few different terms have been used such as: light smoker; non-daily smoker; occasional smokers. This is mainly because no one can agree on a consistent definition, and several have been used across the studies investigating this group. Firstly, light and heavy smoking has been used to highlight the contrast between consumption levels. However, this classification is associated with the largest range of criteria between studies (Husten 2009) Secondly, daily and non-daily (or intermittent) smoking is associated with a much more consistent pattern of use in contrast to light and heavy smoking (Shiffman et al. 2012a; 2012b; 2014). This is due to the number of cigarettes per day fluctuating, but smoking less than daily is a key indicator of this consumption pattern. Finally, there is a dichotomy between low and high nicotine dependence. This also appears to be a valid characterisation as non-daily/light smokers consistently exhibit significantly less nicotine dependence on every common measure (Shiffman 2012b). However, it is important to note that in reality, dependence and smoking behaviour exists along a continuum. Even within different dichotomies, there is a large amount of variation across the supposedly homogeneous sub-groups.

Measuring light and heavy smokers

On a final note of measurement, it is crucial to ask the right questions when assessing light smokers. Many questionnaires simply ask ‘are you a smoker?’ which may not detect non-daily smokers as they commonly do not identify with being a smoker (Schane et al. 2009). For example, in one study approximately 50% of light smokers said they might not admit to being a smoker (Shiffman et al. 2013). This suggests simply asking whether people smoke or not might not be the best strategy, as they may just get ‘no’ as an answer. Clearly, more nuanced approaches are necessary to detect the low number of cigarettes consumed by this group. Fortunately, there are some additional measures of cigarette consumption that can provide a more sensitive answer:

  • A diary measure of the number of cigarettes smoked over a period of time
  • Breath Carbon Monoxide (CO) in a single session
  • Average CO over a number of sessions
  • Hair cotinine (a metabolite of nicotine) or nicotine levels

However, what are the best measures to use? An intensive diary account is considered to be the most accurate but it is the most time consuming for smokers which may deter some participants (Wray, Gass and Miller 2015). When comparing this to the less motivationally intensive measures, it appears that a single daily report of cigarettes across a number of days is the measure most strongly correlated with the intensive diary. Furthermore, when the level of exhaled CO is averaged across multiple testing session, this provides a valid biomarker for measuring cigarette consumption in light smokers (Wray et al. 2015). As well as these accuracy benefits, using a handheld CO monitor is cheap and does not require the expertise associated with analysing hair cotinine and nicotine levels. Due to the heterogeneous nature of smokers, it is crucial that the complexities in identifying light smokers are fully appreciated.

Conclusion

In summary, there is a clear distinction between different types of smoker but it is often neglected in research. Despite an apparent lack of nicotine dependence, both types of smoker find it difficult to remain abstinent with only a small difference between the cessation failure rates (Tindle and Shiffman 2011; Herbec et al. 2014). This is important for public health as although they form a minority of smokers, they share the same risk factor for heart disease as heavy smokers, and have an elevated risk of lung cancer (Bjartveit and Tverdal 2005; Schane et al. 2009). Considering the number of light smokers is predicted to increase as smoking restrictions tighten (Coggins et al. 2009; Shiffman 2009), it is crucial that this group is understood better. Research should focus on the individual differences in the determinants of smoking behaviour to better understand what is motivating light and heavy smokers. This knowledge will hopefully translate into more effective smoking cessation treatments that cater to the individual needs of each smoker.

 

Reading List

Health implications: Schane, R. E., Ling, P. M., Glantz, S. A. (2010) ‘Health Effect of Light and Intermittent Smoking: A Review’. Circulation 121, 1518-1522

Smoking Patterns: Shiffman, S., Tindle, H., Li, X., Scholl, S., Dunbar, M. and Mitchell-Miland, C. (2013) ‘Characteristics and Smoking Patterns of Intermittent Smokers’. Experimental and Clinical Psychopharmacology 20(4), 264-277

Smoking Motives: Shiffman, S., Dunbar, M. S., Scholl, S. M. and Tindle, H. A. (2012a) ‘Smoking Motives of Daily and Non-Daily Smokers: A Profile Analysis’. Drug and Alcohol Dependence 126, 362-368

Definitions: Husten, C. G. (2009) ‘How Should we Define Light or Intermittent Smoking? Does it Matter?’. Nicotine and Tobacco Research 11(2), 111-121

Measurement: Wray, J. M., Gass, J. C., Miller, E. I., Wilkins, D. G., Rollins, D. E. and Tiffany, S. T. (2015) ‘A Comparative Evaluation of Self-Report and Biological Measures of Cigarette Use in Non-Daily Smokers’. Psychological Assessment [online] available from http://www.ncbi.nlm.nih.gov/pubmed/26479132  [12/07/2016]

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What Do Whigs Have To Do With History of Psychology?

The 2013 December issue of the journal Theory & Psychology saw a forceful exchange between Kurt Danziger and Daniel N. Robinson on the nature of psychology’s disciplinary history. For those unfamiliar with the names, both are eminent scholars in (among other things) history of psychology. The exchange boils down to Danziger accusing Robinson of creating a romanticized history of psychology, tying the discipline down to Ancient Greek philosophies.  What Danziger cannot forgive in such a way of writing history of science is the idea of a concept that stays the same throughout history, and then finds its way into psychology. For example (Danziger, 2013, p. 835): “This understanding of psychology’s history has always relied on the belief that the concept of ‘human nature’ represents some historically unchanging essence guaranteeing continuity, no matter how great the gulf that appears to separate the present from the remote past.” Robinson, in turn, answers with two articles in the same issue defending his position with insinuations that Danziger and his supporters are not familiar enough with Aristotle’s body of work to mount such a criticism. His repartees, sans the scholastic posturing, can be summed up well with the sentence (Robinson, 2013a, p. 820): “It is worth noting in order to make clear that the past can be highly instructive without being causally efficacious.” Continue reading

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The Impostor Syndrome

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It has become increasingly clear that academia is rife with a condition known as the ‘impostor phenomenon’. The term was coined in 1978 by psychologists Clance and Imes in describing a sample of high-achieving women who were not able to internalise their many successes. Like many others today, these women felt that they had gotten to their place in life only by a series of flukes. The so-called syndrome can be debilitating; those with it feel like frauds and, worst of all, that at any moment they could be found out and exposed (Gravois, 2007). Recently, more and more people in academia have ‘admitted’ to having the impostor syndrome.

 

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Why meta-analysis? A guide through basic steps and common biases

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 Meta: meta- combining form. From Greek meta ‘with, across, or after.’  Pertaining to a level above or beyond.

 Analysis: analysis |əˈnaləsis| noun. From Greek analuō ‘I unravel,  investigate’. Detailed examination of the elements or structure of  something,
 
Often times, researchers and students find themselves going through a  dense amount of papers on a certain topic only to find results that don’t  really seem to point towards a coherent or homogenous conclusion. Does this treatment work?
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How to Read and Get the Most Out of a Journal Article

Journal articles are read by researchers or students for various reasons, but mainly, for reviewing for conferences, classes, research projects, or simply to keep up with the latest developments in one’s field of interest. However, effective reading skills are rarely taught or brought up for discussion as a prominent issue that needs more attention. Thus, many of us spend hundreds of useless hours trying to master this skill. Why not to save ourselves time and effort by following just few simple steps?

 

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Research Proposal: Behind-the-Scenes Exclusive

Staying in academia involves writing up research proposals. For some, it starts as early as during their Bachelor’s studies where they have to provide one-page experiment proposal for their supervisors. Then, after several discussions with the supervisor, they may begin their very first research experiment. Later in time, other coursework comes in – where in order to pass the subject – one must carry out an experiment that makes sense. For many students, the last time (or sometimes the first and only time) they wrote something similar to a research proposal is, when they begin their Master’s thesis. At this level, a good outline of the research is unavoidable and usually mounts up to 3-5 pages. Of course, it is possible to slip-through the system without approaching the thesis-writing preparation seriously, but usually such approach ends up in much more negative feelings than simply outlining the strategy and planning for the research.

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Life is a box of chocolates

Sitting in a classroom and being lectured, I often felt a sense that I should not question what I am being taught. This was not due to any fault of the lecturers who mostly were very welcoming of students’ opinions. However, simply knowing that this was an area that they had spent years researching and seeing them sharing at their computers screen, or head in a book every time you look through their office window gave the sense that they must have all the answers and have a justified reason for their opinions whereas mine always felt too subjective to be taken seriously. During my undergraduate degree, my essays became more and more focused on the areas which we had been taught in class and less inclusive of the breath of what were my own opinions. This was simply because having a controversial argument seemed to lead to more frustration in conceiving the lecturer’s than arguing what was the ‘popular’ approach.

 

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What makes a good research question?

You are sitting in front of the computer, staring at one of the thirty browser windows that you have opened as a result of your online search for a research topic. For the past few days, you have been going round in circles, trying to nail down a research problem to work on, but to no avail. In fact, as a last resort to this exasperating quest, you have now decided to Google for “how to find a research topic”. If this sounds familiar, it is because it is not new. If you have the experience of conducting your own study, chances are, at the early stages of your research, you have faced with the difficulty of deciding on a research question and have constantly wondered if you were asking the right question. In truth, the search for a good research question is a daunting task, especially when researchers are often expected to know how to identify or figure out a good research question on their own.

Fortunately, with every problem, there is always a place at which we can use as a starting point that will hopefully lead us to a desirable solution.

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Evaluating qualitative research: Are we judging by the wrong standards?

Although qualitative research methods have grown increasingly popular,confusion exists over how their quality can be assessed and the idea persists that qualitative research is of lesser value when compared to quantitative research.  Quantitative and qualitative research have different historical roots and are based on very different concepts, yet the dominance of positivist ideas about what constitutes good quality, valid research in psychology has often led qualitative research to be evaluated according to criteria, that are designed to fit a very different paradigm.  Inevitably, the diverse perspectives which use qualitative methods and their differing views on how people should be studied mean there is disagreement and controversy over how quality should be evaluated.  Despite this, it is seen as important to develop common criteria which allow the quality of qualitative research to be evaluated on its own terms.

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Research oriented social networking?

Taking your first steps in the world of academia can be intimidating. We have all experienced it while preparing research proposals, sitting in exams, and discussing research projects with peers and professors. What can make it easier is the thriving research community you can find online. By participating in it, you can create connections, find information, learn and enhance your skill-set in research, scientific writing, and so much more. However cliche it might sound, participating in the community is a great investment in the future.

What are, then, the best places to look for research-oriented social networking? Where do Internet personas of researchers and students congregate? Read on and find our suggestions. Continue reading

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