In this series, I’ll be investigating different drugs, busting some myths and explaining potential harms and benefits. This week it’s the turn of tobacco
What’s the appeal?
Tobacco, the dried leaf that’s smoked in cigarettes, cigars and pipes, and taken in various other forms such as snus and chewing tobacco, has been used as a recreational drug for hundreds, if not thousands of years. Cigarettes as a method for smoking became popular during World War one, when they were included as part of soldiers’ ration packs. People who smoke report that it relives stress, and can make them feel calmer and more relaxed. But is this really the case? Two in three smokers will have started smoking before the age of 18, and smoking is illegal in this age group, in the UK and many other countries around the world. The percentage of current smokers who want to quit is similarly high (around 2 in 3 current smokers report wanting to quit).
Short term effects
While there’s no real intoxication effect of cigarettes, if a person is not used to nicotine, a cigarette can make them feel sick or dizzy. Smoking a cigarette raises your heart rate. If a person is a regular smoker and addicted to nicotine, then smoking a cigarette can bring a person out of withdrawal. Nicotine withdrawal is characterised by feelings of anxiety, irritability, headaches and difficulty concentrating. It could be that the reason smokers report that cigarettes lower their anxiety and stress is because of the alleviation of these withdrawal effects – indeed, this seems likely, as long term use of cigarettes is associated with higher levels of depression and anxiety.
The health impacts of cigarettes have been known for well over half a century. Cigarettes are responsible for the premature deaths of 2 in 3 users, according to recent figures from the UK and the USA. Smoking causes lung cancer, and at least 13 other types of cancer, to a varying degree. Cancer Research UK estimate that smoking causes a quarter of all cancer deaths in the UK, and nearly 1 in 5 cancer cases. Smoking also increases the risk of heart disease and lung disease aside from cancer.
There has been some suggestion that smoking, or nicotine in particular, might be beneficial for Parkinson’s disease. Indeed, Parkinsons UK have funded research looking in to this. However, as yet the evidence is thin on the ground, and there’s some reason to believe that this seemingly positive association might be a statistical artefact. Given that smoking kills so many people who do it, the smokers who survive long enough to be at risk of Parkinson’s disease might be an unusually hardy bunch, so it could be this rather than the nicotine that’s protective against Parkinson’s. Elderly smokers represent a really interesting population to research for this reason, if we can identify why they don’t succumb to smoking related illnesses, this might be extremely useful for designing treatments for others.
Nicotine is extremely dangerous: While nicotine is the addictive substance in cigarettes, it’s not the really harmful part of them. The process of burning tobacco releases carbon monoxide, hydrogen cyanide, at least 70 known carcinogens, and a variety of other chemicals. Nicotine is addictive, but specifically in cigarettes rather than in other forms, as tobacco’s acidity in cigarettes differs from cigars and chewing tobacco, meaning that nicotine is absorbed through the lungs when smoking cigarettes, giving a much more immediate hit. Cigars, inhalators, nicotine gum and patches all have a slower effect due to the nicotine being absorbed through the mouth or skin, and therefore taking longer to reach the brain.
Shisha is less harmful than cigarettes: A lot of people assume that shisha is less harmful than smoking cigarettes, because the smoke is cooler, and because of the flavouring, some people assume that shisha doesn’t contain tobacco. However, most commonly shisha will contain tobacco, and although the smoke is cooler, very little filtering of the smoke occurs as it passes through the water, and the current evidence suggests its unlikely to be less harmful than cigarattes. However, given different smoking patterns when using shisha compared to cigarettes, direct comparisons are hard. Although shisha sessions often last a lot longer, they are undertaken much less frequently. And far less research has been conducted on the effects of shisha, as compared to cigarettes. Even so, it seems that shisha is not as safe as a lot of people seem to assume it is.
Menthol cigarettes are safer/menthol cigarettes are more harmful: There is disagreement even among the myths surrounding menthol cigarettes. Again, there’s been less research conducted on menthol cigarettes compared to regular cigarettes, but there’s no evidence to suggest they’re any more or less harmful – it seems likely that they’re just as harmful as regular tobacco.
Roll-ups and natural tobacco are less harmful: It’s a common belief that rolling tobacco contains less of the harmful chemicals and components than machine made cigarettes. This is a myth. Some studies have found that rolling tobacco actually contains more additives than factory made cigarettes, and one animal study suggested that rolling tobacco was more addictive, although this was a small study.
Light or low tar cigarettes are less harmful: You may have noticed that there’s no such thing as Marlboro lights any more. Tobacco companies are no longer allowed to market cigarettes as ‘light’, since light cigarettes were no less harmful than regular cigarettes. And this was due to the difference between humans and machines. Light cigarettes were created by altering the filter – more holes were added to it, with the idea being that smoke would escape before being inhaled, so less harmful particles would be breathed in. This was tested using machines that ‘smoked’, and lo and behold, this was the case. The machines ‘inhaled’ lower levels of smoke. But humans aren’t machines, and altered their smoking patterns, squeezing at the filters and dragging more deeply on the cigarettes, meaning any benefit of the altered filters was lost.
Cutting down smoking will reduce the levels of harm from smoking: It seems hard to believe that this isn’t the case, but cutting down the number of cigarettes you smoke doesn’t necessarily reduce the risk of smoking-related harm. This is related to the myth above – if a person is used to getting a certain amount of nicotine in a day, then if they smoke fewer cigarettes, they’re likely to draw more deeply, take more puffs, and hold the smoke in their lungs longer for the cigarettes they do smoke. Psychologically, cutting down is a great first step in the quit process, but in terms of harm reduction, quitting is really the only way.
What do we still not know?
You might think that we know all there it to know about cigarettes and tobacco. We’ve known for more than half a century that smoking causes lung cancer, and the physical effects of smoking are fairly well understood. But there is still a lot that we don’t know. For example, why do some people find it really easy to quit smoking, while others really struggle? There’s evidence that smoking behavior is partly genetic. Genotype predicts how heavily a smoker will smoke, and can affect it up to the level of a couple of cigarettes extra per day. This might go some way to explaining why it’s easier for some to give up than others, and could even represent a method to work out how to help a person to quit. If your addiction is stronger, maybe you’ll need pharmacotherapy rather than trying to quit cold turkey, for example.
The other emerging area of research that I’m really interested in is trying to understand why smoking rates are so much higher in populations with mental health difficulties. We understand the physical effects of tobacco so well, but we’re much less sure about why these associations come about.
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