Drugs and health
Drugs are substances that have effects on the body.
• Medicines are drugs that help people suffering from pain or disease.
• Recreational drugs are taken for pleasure.
Some recreational drugs are legal, such as tobacco, alcohol and caffeine. Legal drugs are that are prescribed to a patient by their doctor or bought over the counter. Most other recreational drugs are illegal, such as cannabis, ecstasy and heroin. Illegal drugs include prescription drugs that have been dangerously modified and substances that are banned by law.
Problems with drug use
Recreational drugs can be classified as depressants or stimulants. Most recreational drugs can be addictive. Recreational drugs are taken by people to alter their mood. Many drugs alter the chemical processes in the body in such a way that the person taking them becomes addicted to them. They feel they have to take the drugs, and they suffer unpleasant withdrawal symptoms if they stop taking them. All four drugs listed above are addictive. Heroin and cocaine are very addictive, and may cause permanent mental problems.
All drugs have the potential to damage our health, because they change chemical processes in the body. Addictive recreational drugs may damage our health indirectly by reducing the amount of money available to buy food, and by placing users in dangerous situations. Users of illegal drugs may turn to crime to pay for their habit, and this affects the lives of other people.
All drugs can damage the liver, because it is the liver that breaks drugs down in the body. Any drug that is misused can cause damage to the body, as well as personal and social problems. Injecting any drug with a needle and syringe that someone else has used may lead to a number of diseases from infected blood, including HIV and hepatitis.
Depressants slow down messages in the brain and along the nerves. Alcohol is a depressant. It is found in beer, wines and spirits such as vodka.
Other depressants include cannabis, heroin and solvents (eg glue and aerosols).
Here are some of the typical effects depressants have on the body:
• feelings of well-being
• lowered inhibition
• slowed thinking
• slowed muscular activity
• a distorted view of the world, or hallucinations
Some of the long-term effects of depressants on the body include damage to the liver, brain and heart. They can also have the following effects:
• alcohol can cause weight gain
• solvent abuse causes a rash around the nose and mouth
• cannabis causes loss of memory and concentration, as well as an increased risk of mental illness.
Stimulants speed up messages in the brain and along the nerves. This makes you feel more alert. Caffeine is a stimulant and is found in cola drinks, coffee and tea. It makes you feel more energetic and alert, but it can also cause insomnia (difficulty in sleeping), headaches and nervousness.
Cocaine, ecstasy and amphetamines are all illegal stimulants. They make you feel more energetic and confident, but they can damage the liver and heart. They can also cause loss of memory and concentration, and bring an increased risk of mental illness.
Drugs and drug testing
Drugs are substances that cause changes to the body. Some drugs can help the body, but others can harm it. Some drugs can be extracted from natural sources and their existence has been known about for a long time. For example, willow bark is known to have been used by the by the Ancients Greeks to help cure fevers and pains. It was later discovered that the active ingredient was salicylic acid. This was modified by chemists into the substances we call aspirin, which is less irritating to the stomach than salicylic acid.
New medical drugs have to be tested before they can be prescribed for patients. They are tested in a laboratory to check that they are not toxic, and later they are trialled using human volunteers. At this point, any potential side effects should show themselves. Most substances do not pass all the tests and trials, so drug development is expensive and takes a long time.
Medical drug trials are not without risk. Sometimes very severe and unexpected side effects appear.
Types of drug
A drug is a substance taken into the body that modifies or affects chemical reactions in the body. Some drugs are beneficial, while others are harmful.
Type of drug Effect on body Example
Depressant Slows down nerve and brain activity Alcohol, solvents, temazepam
Hallucinogen Alters what we see and hear LSD
Painkiller Blocks nerve impulses Aspirin, paracetamol
Performance enhancer Improves muscle development Anabolic steroids
Stimulant Increases nerve and brain activity Nicotine, caffeine, ecstasy
Stimulants and depressants affect the synapses between neurones in the nervous system:
• stimulants cause more neurotransmitter molecules to diffuse across the synapse
• depressants stop the next neurone sending nerve impulses. They bind to the receptor molecules the next neurone that needs to respond to the neurotransmitter molecules.
Classification of drugs
Some drugs are illegal, or must only be prescribed by a doctor. Some prescription drugs are misused and taken for recreational use, rather than for medical reasons. They become illegal under these circumstances.
Illegal drugs are classified from Class A to Class C. Class A drugs are the most dangerous, with the most serious penalties for possession or dealing. Class C are the least dangerous, with the lightest penalties, but this does not mean they are safe to use.
Classification of drugs
Class of drug Examples Penalty for possession penalty for dealing
Class A ecstasy, LSD, heroin, cocaine, crack, magic mushrooms, injected amphetamines Up to seven years in prison or an unlimited fine, or both Up to life in prison or an unlimited fine, or both
Class B amphetamines, cannabis Up to five years in prison or an unlimited fine, or both Up to 14 years in prison or an unlimited fine or both
Class C tranquilisers, painkillers Up to two years in prison or an unlimited fine or both Up to 14 years in prison or an unlimited fine, or both
Illegal drugs are classified from Class A to Class C. Class A drugs are the most dangerous, with the most serious penalties for possession or dealing. Class C are the least dangerous, with the lightest penalties, but this does not mean they are safe to use. The table above shows some of the drugs in each class.
Illegal drugs include prescription drugs that have been dangerously modified, and substances that are banned by law. Ecstasy, cannabis and heroin are illegal recreational drugs. Using them can cause health problems.
Heroin is an illegal recreational drug which can damage the heart and circulatory system
Heroin and cocaine are very addictive. Like ecstasy, they can damage the heart and circulatory system. Cannabis contains chemicals that cause mental illness in some people.
Recreational drugs, both legal and illegal, may also damage our health indirectly. For example, buying the drugs reduces the amount of money available to buy food, and may place users in dangerous situations.
Injecting a drug with a needle and syringe that someone else has used may lead to a number of diseases from infected blood, including HIV and hepatitis. Users of illegal drugs may turn to crime to pay for their habit, and this affects the lives of other people.
Smoking and health
Most people start smoking before they are adults
Smoking is very harmful to our health. Thousands of people die every year in the UK as a result of smoking-related illnesses.
Warnings such as ‘Smoking can cause a slow and painful death’ are used to deter people from smoking.
About 114,000 people die every year as a result of smoking-related illnesses. All cigarettes sold now carry a prominent health warning.
Cigarettes contain about 4,000 different chemicals, many of which are harmful to the body.
Smoking is very harmful to health. It causes around 80 per cent of deaths from lung cancer, bronchitis and emphysema in the UK, and almost a fifth of UK deaths from heart disease.
Tobacco smoke contains many harmful substances. These include:
• carbon monoxide
Tar causes cancer of the lungs, mouth and throat. It coats the surface of the breathing tubes and the alveoli. This causes coughing and damages the alveoli, making it more difficult for gas exchange to happen.
The images above compare a healthy lung to a smoker’s lung. Tar deposits can be seen clearly in the smoker’s lung.
Cells in the lining of the breathing tubes produce sticky mucus to trap dirt and microbes. Cells with tiny hair-like parts, called cilia, normally move the mucus out of the lungs.
Hot smoke and tar from smoking damages the cilia. So smokers cough to move the mucus and are more likely to get bronchitis.
Nicotine is addictive – it causes a smoker to want more cigarettes. It reaches the brain within 20 seconds and creates a dependency so that smokers become addicted. Nicotine also increases the heart rate and blood pressure, and makes blood vessels narrower than normal. This can lead to heart disease.
Carbon monoxide combines with the haemoglobin in red blood cells and so reduces the ability of the blood to carry oxygen. This puts extra strain on the circulatory system, and can cause an increased risk of heart disease and strokes.
Smoking during pregnancy is very dangerous. It reduces the amount of oxygen available to the growing foetus. This leads to an increased risk of
• miscarriage and premature birth
• low weight of babies at birth
Carcinogens are substances that cause cancer. Tobacco smoke contains many carcinogens, including tar. Smoking increases the risk of lung cancer, mouth cancer and throat cancer.
Smoking and lung cancer
The graph below shows the change over time in cigarette consumption and the incidence of lung cancer.
In 1975, the male:female ratio for lung cancer cases was around 39:10, but has fallen sharply since then to 12:10 in 2010.
The alcohol in alcoholic drinks (such as wines, beers and spirits) is called ethanol. It is a depressant – it slows down signals in the nerves and brain.
Small amounts of alcohol help people to relax, but greater amounts lead to a lack of self-control. Drinkers of alcohol may not realise how much they are consuming, and fall ill as a result. They may become unconscious, and may even fall into a coma.
There are legal limits to the level of alcohol that a driver or pilot can have in their body. This is because alcohol decreases reaction times (ie makes them longer) and impairs the ability of people to control their vehicles properly. The police use breath tests and blood tests to see if a driver is over the limit.
The liver removes alcohol from the bloodstream. It has enzymes that break down alcohol but the products of the reactions involved are toxic.
Short-term effects of alcohol:
• Sleepiness and impaired judgement, balance and muscle control. This leads to blurred vision and slurred speech.
• There is an increased flow of blood to the skin, which can cause reddening of the skin.
• Vasodilation occurs – blood vessels in the skin carry more blood – leading to heat loss.
Long-term effects of alcohol:
• Damage to the liver and brain. Alcohol damages the liver and, over time, this leads to cirrhosis.
• Alcohol may also cause weight gain, and it is addictive.