Drugs are everywhere. Most people take some kind of drug fairly regularly. Not all drugs are the same though.

A drug is basically any chemical which alters how the body works, or how a person behaves or feels. There are different risks attached to different drugs, but almost all drugs are addictive and abuse leads to serious mental and physical problems.

The Oxygen guide is only a very basic introduction. If you are having problems with drugs then you should contact someone who can help. There's a phone number at the bottom of the page.

Here's a breakdown of some of the most common drugs out there:

Tobacco
The most widely used stimulant is the drug tobacco, generally smoked in cigarettes. The leaves of the tobacco plant contain a chemical, nicotine, which affects the heart, blood vessels, stomach, kidneys and central nervous system.

Experience: It gives a feeling of relaxation and may help the smoker face stressful situations more easily.

Effects: People who smoke are more likely to suffer from various health problems including; heart disease, blood clots, heart attacks, bad circulation, ulcers, lung infections, bronchitis and 90% of lung cancers are believed to be caused by the chemical components in cigarette tar. It is also extremely addictive.

Alcohol
One of the most commonly used drugs of all, alcohol comes in many different forms like wine, beer and spirits. Alcohol is notoriously a depressant.

Experience: It helps people relax socially. They can become more animated and it can appear to drown worries. It has been known to increase sexual desire.

Effects: Within safe limits, alcohol is not dangerous. But drinking too much can cause vomiting, dehydration and hangovers. It has been related to violence more than any other drug. It is both physically and mentally addictive and drinking too much over a long period of time can cause liver damage.

Cannabis
This comes in the form of dried leaves from the plant, or resin, which is usually smoked in a cigarette called a joint or spliff. It can also be baked into cakes. Cannabis is one of the most commonly used of all illegal drugs. It goes by many names including hash, blow, marijuana, spliff, hemp, draw, smoke etc, etc.

Experience: Users experience feelings of relaxation and euphoria and become receptive and sociable towards those around them. It can also increase the appetite of users.

Effects: Some users report reactions of fearfulness, confusion and anxiety. Long term use has been linked to memory loss, paranoia and lethargy. Smoking joints carries an even greater risk of certain forms of cancer than smoking cigarettes and may lead to an increased risk of acute and chronic bronchitis.

Amphetamines
Speed generally comes in powder form and is snorted up the nose. It can also come in pill form or be injected.

Experience: Speed is a powerful stimulant which speeds up the entire nervous system. Energy and movement increase rapidly. Users may talk very quickly and find it difficult to keep up with their thoughts.

Effects: Users often experience feelings of tiredness and depression afterwards, and in the long run, can feel physically and emotionally exhausted. The drug is psychologically addictive and regular users can find it difficult to give up.

Cocaine
Cocaine is a white crystal-like powder without a smell. Cocaine is normally sniffed, but it may also be injected. Can be called 'coke'.

Experience: The person who is taking cocaine will rarely feel hungry or tired and can stay awake for long periods. He feels superior and very confident and sometimes becomes aggressive.

Effects: Cocaine is likely to produce dependence because after the buzz wears off, the person can be left feeling very depressed. The easy way to feel great again is to have some more. This can lead to users finding they are taking it all the time, and increasing the amount used. This can lead to users neglecting their health, eating and sleeping.

Ecstasy
Ecstasy usually comes in tablet or capsule form. The main ingredient in E is a chemical substance called MDMA, but this is often mixed with other ingredients, such as amphetamines or tranquillisers.

Experience: Ecstasy is usually taken at raves or nightclubs to produce a feeling of relaxation with increased energy, happiness and flexibility. Users can feel less inhibited and mellower, and experience everything more intensely. Ecstasy takes effect in 20-60 minutes, usually is at its height for about 2 hours, and can last for several hours after that.
effects: Taking any stimulant increases body temperature. The hot atmosphere of a dance floor and the dancing itself raises it again, so that ravers start losing fluid (dehydrating). They need to take a pint of fluid (not alcohol - it also dehydrates) per hour to avoid heat-stroke which has killed ecstasy users here and in other countries. This is best done by sipping no more than a pint of water, fruit juice or isotonic drink in any one hour.
short-term effects: These may include intense sweating, dry mouth, loss of appetite, increase in heart rate and blood pressure, nausea, and sometimes pain and stiffness in arms, legs and jaws. This pressure on the heart and respiratory system can kill after a single dose. Anyone suffering from epilepsy, diabetes, asthma or pre- existing heart disease is particularly vulnerable to having symptoms brought on suddenly with severe consequences.

Long-term Effects: These can include insomnia, lethargy, anorexia and weight loss. Other effects may include psychiatric problems such as depression, anxiety and panic attacks. Although ecstasy is not physically addictive, users may become psychologically dependent on the drug.

Heroin
One of a number of opiates derived from the poppy plant, heroin comes most commonly in the form of a white powder which is either injected (after being mixed with water) or smoked. It is also known as horse, smack, H, or gear.

Highs: Heroin creates a rush of pleasure and users tend to feel they cannot be harmed and may feel detached from the outside world.

Lows: Heroin is, both physically and emotionally a highly addictive drug. Withdrawal, once addicted, is difficult, and the symptoms include drowsiness, sweats, anxious breathing, vomiting and possibly even coma. Overdosing can be fatal, as can combining it with large amounts of alcohol. Sharing needles carries a greater risk of infection with HIV, AIDS and hepatitis.

What to do if you know someone is abusing drugs
Firstly, get advice from a parent or counsellor. Any drug user should be referred to a doctor, college counsellor, community addiction counsellor, or the Drug Treatment Centre, Trinity Court, Pearse Street, Dublin 2, Tel: 01 - 6771122.