Understanding tobacco addiction

You have heard time and time again that smoking is detrimental to health. It says it on the packaging, it says it on the adverts, it says it on the posters and yet you see people lighting up a tobacco filled tube at every nook and corner. Why, given all these warnings do people continue to smoke? 

Among the negative health outcomes of smoking, addiction is seen as a principal culprit. The smoke contains psychoactive substances such as nicotine that bind to the special nicotine receptors found in the central nervous system of our body and trigger the reward mechanism of our brain that releases dopamine, the neurotransmitter of pleasure, eventually elevating the mood and causing euphoria or calmness. This reward serves as a positive reinforcement that pushes the smoker to burn through more and more cigarettes over time. Addiction leads to compulsive smoking that eventually induces dependence. Nicotine dependence is the strong, overpowering desire to smoke due to its rewarding outcomes and also to avoid withdrawal symptoms (i.e irritability, aggressiveness, sleep disturbance) Exposure to high concentrations of nicotine desensitizes the aforementioned nicotine receptors thus creating a phenomenon called “tolerance” where a higher dose of the substance is needed to create the same effect. This desire dominates the lifestyle as well as the quality of life of the smoker that causes harm to himself as well as the community.

According to a study by the Alcohol and Drug Information Center, 33% of the male population above the age of 15 are tobacco smokers. Smoking in females is not that uncommon either. Tobacco was chewed and smoked through pipes during out great grandparents’ years whereas cigarettes owe up to 98% of the tobacco consumption in the modern day.

QWhat does a cigarette contain?
 It is important to know the contents of a cigarette since most of them are present in the body of a smoker and to a lesser extent in people who inhale second-hand smoke (the involuntary inhalation of smoke from other people’s cigarettes) and third-hand smoke ( residual nicotine and chemicals left on various indoor surfaces). The latter two are also known as passive smoking, both posing as a significant health hazard in non-smokers exposed to it. Tobacco contains the chemically active compound nicotine (a neurotoxin similar to most venoms found in animals but in lower concentrations) as its main component apart from carcinogenic (causing cancer) tars and carbon monoxide (CO) that is a toxic gas making up 50% of the cigarette while the remainder constitutes of certain ‘add-ons’ that enhance the absorption of nicotine to the body. Tars are toxic components that are also responsible for the brown staining of teeth and skin and easily reflects the staining of lungs and the entire respiratory and alimentary passages.  

The number of chemical compounds within the cigarettes and produced when lit up is by the thousands with most of them considered to be highly toxic and carcinogenic. For example acetone-a chemical found in thinner, ammonia-found in disinfectants, fertilizers and explosives, anabasive-an industrial insecticide, heavy metals such as chromium that is found in paint, mercury, lead- found in batteries and bullets and also a potent neurotoxin that builds up within human soft tissue and damages the nervous system. Hydrogen cyanide-considered a highly toxic substance used to temper steel and create explosives and sadly used by the Nazis for genocide in gas chambers. Research has revealed more than 60 carcinogenic chemicals found in cigarettes including acetaldehyde that is an intermediate of many chemical reactions, arsenic found mostly in pesticides and herbicides, benzene- found in rubbers and dyes, cadmium, formaldehyde-used in preservation of human corpses and body parts, Nickel-found in stainless steel.

Average cigarette contains 0.8g of tobacco and 9-17mg of nicotine, of which 10% is absorbed by the smoker, increasing the body’s nicotine concentration upto 100-200 nmol/l. Nicotine is rapidly absorbed in the body by lungs and poorly absorbed through the mouth and nasopharynx thus making inhalation mandatory to achieve reasonable absorption. The nicotine concentration in the body varies with the smoking habits of a person hence provides a useful measure of his smoking behaviour. The inhaled substance (containing about 4000 chemical compounds and among those, 60 known carcinogens) is distributed all over the body that contribute to the unfavourable health outcomes discussed below. In addition, metabolism of these compounds within the body, adds up to the number of toxic contents. 

(Stay tuned to Health Capsule for more information on health complications caused by smoking)