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Types of Drugs

The most commonly encountered drugs of abuse can be split into five main chemical groups. Here is a brief summary of what they are and the effects.

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Diamorphine (Heroin) - Class A

The name heroin comes from the original trademark for the drug diamorphine and as such the two terms are sometimes used interchangeably. In the UK heroin usually refers to the mixture of various drugs obtained during the preparation of diamorphine from morphine that has been extracted from the opium poppy. Because of their origin these drugs are known as opiates. Opiates are highly effective painkillers, with diamorphine being the strongest. In its pure form diamorphine is a white powder, however heroin sold on the street is usually brown in colour.

The Effects

Heroin and other opiates are sedative drugs that depress the central nervous system. They slow down body functioning, and are highly effective against both physical and emotional pain. The effect is usually to give a feeling of warmth, relaxation and detachment with a lessening of anxiety. Effects start quickly and can last several hours but this varies with how much is taken and the method used to administer it. Overdosing can lead to slow breathing and respiratory failure, possibly causing coma and death.


Cocaine and Crack Cocaine - Class A

Cocaine is produced from the leaves of the coca shrub. In the UK and USA the most common form of cocaine is a white crystalline powder which is divided into lines and snorted.

A different form of cocaine comes in the form of small waxy lumps, or ‘rocks'. This is known as ‘crack' cocaine. It is more volatile than powder cocaine and can therefore be easily smoked. Because it can be inhaled higher levels reach the brain much faster compared to powder cocaine which is absorbed more slowly. For this reason ‘crack' cocaine is highly addictive.

Both powder and ‘crack' cocaine can also be prepared for injection. Again this allows high levels to reach the brain extremely quickly and cocaine of any form administered in this way is also highly addictive.

The Effects

Cocaine is a strong, but short acting, stimulant drug. It can make users feel alert and energetic. Many users report feelings of extreme confidence and physical strength and also perceive themselves to have increased mental capacities. Common physical effects include dry mouth, sweating, loss of appetite and increased heart and pulse rate. At higher dose levels users may suffer anxiety and feel panicky. Large doses or quickly repeating doses over a period of hours can lead to extreme anxiety, paranoia and even hallucinations.



The three most commonly encountered amphetamines are amphetamine itself, methylamphetamine, and the Ecstasy-type drugs.


Amphetamine (Speed) - Class B

Amphetamine is a synthetic stimulant. As a street drug amphetamine usually comes as a white, grey, yellowish or pink powder or as putty-like substance known as base. Generally amphetamine will be taken orally or snorted, although it can be prepared for injection. If this is done its classification changes to Class A.

The Effects

In common with cocaine and other stimulants, amphetamine will cause users to feel awake and alert with greater energy and confidence. They may experience reduced boredom and greater cheerfulness. With high doses people often experience a rapid flow of ideas and feel they have increased physical and mental powers. The physical effects include an increase in breathing and heart rate, lessened appetite and widened pupils. Also possible are involuntary body movements and nausea.


Methylamphetamine (Crystal Meth) - Class A

Also known as methamphetamine, this has recently been reclassified from Class B to Class A. Methylamphetamine is much more common than amphetamine in the USA, Australia and New Zealand. Usually in a crystalline form and coarse in texture, it is harder for agents to be added to lessen the purity. As such, methylamphetamine in this form will generally be stronger than amphetamine. In addition, crystalline methylamphetamine ‘Crystal Meth' or ‘Ice' is often smoked or injected, causing greater dosage levels to reach the brain faster than the oral or nasal methods generally used for amphetamine.

The Effects

Since it is very similar chemically to amphetamine, the general effects of methylamphetamine are also similar. Given the purities and methods of administration favoured by methylamphetamine users however it is more addictive and much more potent.

Methylamphetamine users are more likely to experience anxiety, paranoia, aggression and psychotic behaviour compared with amphetamine users.


Ecstasy - Class A

Ecstasy is the widespread name given to any of a group of synthetic drugs, the most common one of which is 3, 4-methylenedioxymethylamphetamine, or MDMA. It is most commonly encountered in tablet form but is also seen as a powder. The colours of the tablets vary and many have logos stamped on them.

The Effects

Ecstasy is a stimulant drug which also has mild hallucinogenic effects, with colour and sound seeming more intense. It has been described as being like a mix of amphetamine and a weak form of LSD. As a stimulant, users will have greater energy and feel alert. In addition it is common for the user to feel a strong emotional bond with the people they are with and strangers around them. Common physical effects include pupils becoming dilated, the jaw tightening, sweating, dry mouth and throat and brief nausea. The blood pressure and heart rate increases and loss of appetite is common. Short term effects can also include anxiety and panic attacks and as the body's temperature regulation is affected there are dangers associated with overheating and dehydration.


Cannabis - Class B

Cannabis is a plant found wild in most parts of the world and is easily cultivated in temperate climates such as the UK's. The main active compound is tetrahydrocannabinol (THC), which has mild sedative and hallucinogenic effects on the brain. Different forms of cannabis come from different parts of the plant and have different strengths. 'Hashish' or 'hash' is the most common form found in the UK - a resin which is scraped or rubbed from the dried plant and then pressed into brown/black blocks. It is also common for dried plant material to be used, traditionally known as ‘grass' or ‘weed'.

In the UK cannabis is usually rolled into a cigarette (or joint), often with tobacco, and smoked. It is the most widely used illegal drug in the UK and by far the one most likely to have been tried by young people.

The Effects

Effects vary between individuals. In general cannabis will make the user feel relaxed and cheerful. The hallucinogenic properties may include a perceived heightened awareness of senses and time distortion. Some users may also experience drowsiness due to the sedative nature of the drug. Use of cannabis causes a number of physical effects including an initial increased pulse rate, decreased blood pressure, bloodshot eyes, increased appetite (‘munchies') and occasional dizziness. Effects start within a few minutes and may last several hours depending on how much is taken.


Benzodiazepines - Class C (tranquillisers, e.g. Valium, prescription drugs which are misused)

All benzodiazepines are prescription only medicines and this makes it illegal to supply them to someone else. Until recently possession without a prescription was not an arrestable offence, with the exceptions of Rohypnol (flunitrazepam) and temazepam. Now a legitimate prescription is required for all benzodiazepines in order to possess them.

The majority of benzodiazepines that are found on the illicit market are diverted from legitimate sources rather than being manufactured illegally. This includes individuals selling part or all of their legitimately prescribed drugs and thefts from manufacturers, pharmacies, hospitals or retailers.

The Effects

Tranquillisers are sedative drugs which depress the central nervous system. They are designed to relieve anxiety and tension and to make the user relaxed. As such it is not difficult to understand why they are used illicitly. They can slow down people's reactions but can also make them feel drowsy, lethargic and forgetful. Effects begin after 10-15 minutes and can last up to 6 hours without repeating the dose.