The Effects & Science of Smoking

Most smokers recognise the health risks associated with smoking. Many smokers would like to quit to prevent further damage to their health, but the World Health Organization (WHO) estimates that less than 5% of smokers trying to quit unaided remain abstinent at one year.

It is believed most smokers continue to smoke not out of choice, but because they are addicted to nicotine. Addiction to nicotine from smoking is a chronic, relapsing medical condition. The addictive properties of nicotine in cigarettes and the psychological and physical dependence caused by smoking explain why people try to stop smoking numerous times before quitting successfully.

What is Nicotine?

Nicotine is a substance found in tobacco plants that may protect the plant from being eaten by insects.
Nicotine has a similar structure to one of the brain’s natural chemical messengers, acetylcholine. Acetylcholine activates the flow of more than 200 neurochemicals which are responsible for many functions of the body, such as the stimulation of muscles. Nicotine binds to the acetylcholine receptors in the brain.

Nicotine easily crosses the blood-brain barrier after a single puff, and influences a range of biological functions.

How does Nicotine Affect the Brain?

  • When inhaled, cigarette smoke travels through the airways in the lungs. From there, nicotine passes directly through the alveolar epithelium into the bloodstream.
  • Although nicotine can interact with a variety of receptors, in numerous tissues, it is its interaction with specific receptors in the brain that creates the dependence associated with smoking.
  • Within seconds, nicotine is delivered to millions of neurons in the central nervous system.
  • Here within the midbrain, nicotine interacts with the alpha-four beta-two (α4β2) nicotinic acetylcholine receptors.
  • This signal is rapidly transmitted down the axon to the reward area of the brain.
  • Here, the impulses stimulate the release of neurotransmitters, including dopamine.
  • Dopamine triggers additional signaling events that stimulate the reward circuit, generating short lived feelings of well-being, improved mood and increased attention.
  • Every time tobacco is used, dopamine levels surge. However nicotine is eliminated rather rapidly, causing dopamine levels to decline.
  • The result – a craving for more nicotine (and more smoking).
  • In summary, the frequent use of tobacco products creates an increased need for more dopamine continuing the devastating cycle of tobacco dependence.

The Effects of Smoking

Worldwide, billions of people smoke.

  • Smoking has been found to harm nearly every organ in the body and is associated with many diseases, including cardiovascular disease, cancer, respiratory disease and stroke.
  • One in two smokers will die from smoking-related illness.
  • For the majority of smokers both the physically and psychologically addictive nature of tobacco products makes quitting difficult.
  • Part of nicotine’s hold on smokers is believed to be due to its effect on brain dopamine levels, which are associated with positive feelings.
  • Knowledge of the receptor activated by nicotine provides helpful insights in the development of new smoking cessation strategies, to help people finally quit smoking.

The Benefits of Stopping Smoking

  • Within hours of quitting, the body begins to repair itself.
  • After 10-15 years of being smoke-free, an ex-smoker has a similar risk of stroke to a person who has never smoked.
  • Stopping smoking at any age reduces the risk of premature death.

Facing up to the Quitting Challenge

  • Quitting takes hard work and a lot of effort. Getting advice, support and medication and being prepared for a relapse can help smokers quit for good.
  • According to the WHO, studies show that even brief advice from healthcare professionals can increase tobacco abstinence rates up to 30%.
  • When smokers stop smoking they experience cravings for cigarettes and withdrawal symptoms that contribute to the likelihood of relapse.
  • Side effects include sleep disturbance, irritability and/or aggression, depression, restlessness and poor concentration.
  • After two to three days of quitting withdrawal, side effects peak and may last for weeks.
  • Successful treatment optimally combines counselling with pharmacotherapy.

Counselling and Behavioural Therapy

Three types of counselling and behavioural therapies have been found effective: provision of practical counselling, provision of social support as part of treatment, and help in securing social support outside of treatment.

Pharmacological Therapy

Effective pharmacotherapies as aids to smoking cessation can be used by appropriate patients attempting to quit smoking.

Stopping smoking is one of the most important steps that smokers can take to enhance the length and quality of their lives.

For more information on smoking cessation services by the National Cancer Society Malaysia (NCSM), visit www.cancer.org.my/quitlikeachamp.
This article is brought to you by Pfizer.