Use and Abuse of Drugs

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Use and Abuse of Drugs
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Drugs are substances that alter the way the body works in some way.  Drugs can be beneficial but may harm the body.  Many drugs can only be used if they have been prescribed by a Doctor.  They may be used to treat, cure or prevent diseases.  Your Doctor may prescribe drugs for a short period of time e.g. antibiotics given to treat an infection or they may be used to treat long-term (chronic) illnesses such as heart disease or cancer.   Many drugs in use today have been developed from natural substances and these were often used originally by indigenous peoples.  Indigenous people are the original inhabitants of an area such as Indians living in the Amazon rain forest or Aboriginals living in Australia.


The pictures show some common drugs.  Coffee, Cigarettes and Wine contain caffeine, nicotine and alcohol which all affect the body.  Cannabis is an illegal drug and prozac can only be used when prescribed by a doctor.  (Photos take from Wikipedia)

Legal Drugs

Cigarettes and alcohol are legal drugs that can be used once you have reached the age of 18.  It is illegal for shopkeepers to sell these drugs to young people under the age of 18.  Alcohol affects the nervous system and slows down reactions and helps people relax.  However, too much alcohol may lead to a lack of self-control, unconsciousness or even coma.  Excessive drinking can damage the liver and brain.

Tobacco smoke contains nicotine which is addictive.  Stopping smoking may cause severe withdrawl symptoms which may be helped by nicotine replacement therapy (NRT).  In NRT the patient is often given controlled doses of nicotine either by sticking a patch on their arm or through the use of chewing gum which contains the drug.  Nicotine is a stimulant (makes you more alert).  Tobacco smoke contains a large number of different chemicals, many of which are carcinogens which may cause cancer.  Tobacco smoke also contains carbon monoxide which reduces the amount of oxygen that can be carried in the blood.  If a pregnant woman smokes, she may deprive the fetus of oxygen and this may lead to a low birth mass in the baby. 


The images show the appearance of a normal liver and the liver from a person with cirrhosis.  Smoking can lead to diseases of the lung such as lung cancer and emphysema.  Amy Winehouse is a well known celebrity who is said to suffer from emphysema.  A normal lung would not have the black patches shown above which are damaged regions of the lung.


Illegal Drugs

Many drugs are illegal wherever they are used, whereas other drugs may be used legally under certain circumstances.  Drugs such as tobacco and alcohol are legal drugs which are used recreationally - i.e. for the enjoyment or pleasure of the user.  Many recreational drugs are illegal and many of these are harmful.

Cannabis is an illegal drug.  The smoke contains chemicals which may cause mental illness in some people and cannabis has been associated with anxiety and depression.  Studies carried out by some scientists appear to indicate that cannabis use may lead to the use of harder drugs such as coccaine or heroin.  However, other scientists believe there is no good evidence  for this.  You need to be able to evaluate these claims critically based upon data that may be presented to you.  If you would like to find out more about these conflicting ideas, click here.

The overall (negative) impacts of legal drugs on health is much greater than the impact of illegal drugs because far more people use them.  For example, overuse of alcohol may lead to people missing days off work due to hangovers or people needing treatment for diseases such as cirrhosis of the liver.  Similarly, smokers are more likely to suffer from ill health than non-smokers.


  Testing new drugs

Thalidomide is a drug that was originally developed as a sleeping pill by a German pharmaceutical company.  Thalidomide was also an effective painkiller.  Shortly after it's first use (in the late 1950s) it was also found to be effective in relieving morning sickness in pregnant women.  However, thalidomide had not been tested for this use.  Thalidomide was in use for around three years and many babies born to mothers who had taken the drug were born with severe limb abnormalities.  Around 10 000 babies were born with limb abnormalities caused by the use of thalidomide around the world.  Germany was the worst affected country followed by the UK.  Once a link between the drug and the birth defects was proven by scientists, the drug was quickly banned and this led to tighter rules for testing drugs before they could be used by patients.  A long campaign run by the Sunday Times eventually led to victims receiving some compensation in the 1970s.  In January 2010, more than 50 years after the drug was first used, the British Government issued a formal apology to those affected.  Around the same time £20 million was awarded in compensation to the 466 survivors.


The baby shown above was born to a mother who had take thalidomide during early pregnancy.

How drugs are tested

New drugs are tested in the laboratory to find out if they are toxic and to find out whether they work. These tests often involve the use of animals. If a drug passes these tests, it is then tested on humans in clinical trials. Very low doses of the drug are given at the start of the trial. If the drug is found to be safe, further clinical trials are carried out to find the optimum dose for the drug. During drug trials, some patients are given a placebo which does not contain the drug. Neither the doctors nor the patients know who has received a placebo and who has received the drug until the trial is complete.

Addiction to Drugs

Initially people take drugs recreationally because of the pleasure and enjoyment associated with their use.  Howewer, over a period of time people need to take the substance in order to feel normal.  Addiction to nicotine in cigarettes is one of the hardest addictions to break and smokers find it very difficult to quit the habit.  The graph below shows the effectiveness of different methods in helping people to quit.

What can be seen is very few smokers manage to quit for more than six months.  Of the different methods used on their own the nicotine nasal spray is the most effective (12% quit smoking).  However, combining a method such as a nicotine inhaler or nicotine nasal spray with intensive counselling leads to a higher percentage of smokers quitting.

The welcome trust has produced some excellent materials on addiction which can be accessed by clicking here.

The link between smoking and lung cancer

It is now widely accepted that smoking tobacco can cause lung cancer.  The link between smoking tobacco and lung cancer was established by the collection of statistics which showed that the more cigarettes a person smoked, the higher the risk of developing lung cancer.  Around 86% of lung cancer deaths in the UK are caused by tobacco smoking and smoking causes more than a quarter of deaths due to cancer in the UK (43 000 deaths in 2007).  For further information click here.

At the end of the second world war over 80% of men smoked some form of tobacco.  Since that time the percentage of smokers has gradually fallen to around 22% of men.  As the numbers of smokers has fallen the incidence of lung cancer in men has also fallen.  The incidence of smoking in women increased slightly between 1948 and 1970 and this is reflected by the slight rise in the incidence of cases of lung cancer in women.  (Don't forget it can take many years for cancer to develop).  The graph below is taken from the Cancer Research UK website

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