Amphetamine is a completely synthetic drug, produced entirely in laboratories.
It was created in the late 1800s by a Romanian chemist and was intended to be a drug for suppressing appetite, so that it could be used for dieting purposes.
But it is very rarely used for this purpose today.
Amphetamine does have a small number of clinical uses.
It is used for treating conditions such as narcolepsy and attention deficit hyperactivity disorder.
A derivative of the drug, called Dexedrine is in usage with the air force in the United States, to keep their pilots focused and alert during long periods of being airborne.
This is done under very strict medical supervision.
But like many drugs, amphetamine is also abused.
The street slang for this drug is 'speed' but there are also derivatives such as ecstasy.
People enjoy the feeling of increased euphoria, energy and focus it gives them.
This results from a surge of the nerotransmitters dopamine, serotonin and noradrenline.
It also blocks the ability of the neurones to effectively deal with these unnaturally high levels of neurotransmitter, so they remain in the synapses.
Abuse of amphetamine can have serious consequences, however.
Users quickly build up a tolerance so that they need to keep increasing the amount of drugs they are taking to achieve the same effect.
Repeated exposure to drugs will cause gradual changes in the brain.
In the case of amphetamine this can cause severe insomnia, paranoid psychosis and mood problems, in particular aggressiveness.
For people with an underlying heart condition or high blood pressure, the increased heart rate it causes can trigger a fatal arrhythmia.