Not so long ago most recreational drugs were known quantities that had been first used in medicine in some form.
Heroin is a derivative of morphine, the most powerful painkiller there is.
Cocaine was once used as an anaesthetic, while ecstasy was used briefly in couples therapy, and amphetamines in some slimming drugs.
But now a new drug called mephedrone, created in a backstreet lab just for recreational purposes, is catching on quickly.
Not to be confused with heroin substitute methadone, it's also known as meph, miaow, bubbles and m-cat.
Virtually unknown in the UK a couple of years ago, a recent online survey by researchers at London's National Addiction Centre revealed that, out of 2,000 readers of clubbing magazine Mixmag, one in three had used the drug in the past month.
Misguided appeal Perhaps this isn't surprising. It costs around £10 a gram and the quality of other recreational drugs has been in steep decline.
Police found recently-seized "cocaine" contained just 15% of the real thing with the rest made up of anything from brick dust to anaesthetic.
But there's another reason for its attraction which I find more disturbing. It's legal to possess it, giving naive would-be users the impression that it must be safe.
That's a very dangerous assumption to make. This drug is so new we know very little about it and its effects.
Because it contains chemicals that have never before been used as drugs, no tests have been carried out to show they are safe.
And there hasn't been enough time for any serious long-term health problems to come to light.
Neither do we know much about how it reacts with other drugs, including alcohol.
Anyone taking it is effectively offering themselves as a lab rat in an unofficial experiment.
Although it's not legal to advertise or sell it for human consumption, cunning online vendors get around the law by labelling it as "plant food".
What we know In the UK, increasing reports of dangerous side effects, some of which have put users in hospital, has led to a review by the Advisory Council on the Misuse of Drugs, which I hope will result in a ban some time this year.
I accept that some people will still take it but it may deter those who mistakenly believe that it's safe because it's legal.
Mephedrone is already illegal in Sweden, Denmark, Israel and Germany, while similar investigation into other party drugs GBL, BZP and Spice resulted in a ban in December 2009.
In the Mixmag survey, half of users reported headaches, four in 10 had heart palpitations, more than a quarter were nauseous, and others had blue fingers, suggesting their circulation had been badly affected.
According to charity Drugscope users have also reported nose bleeds and sore throats as a result of snorting the drug, along with blurred vision, hot flushes, muscle tension, hallucinations, paranoia, compulsion to take more and possible psychological addiction.
What exactly is it?
Mephedrone is a stimulant, derived from cathinone, a chemical found in a plant called khat which comes from Africa.
Chemically it's related to amphetamines and has a similar effect to ecstasy, making users feel euphoric, alert, chatty and generally well disposed towards others.
However, besides the side effects already mentioned, the main downside of amphetamine-based chemicals is that they may overstimulate the heart and nervous system, leading to fits.
3 THAT WERE BANNED RECENTLY
These drugs became illegal in December 2009:
(1)GBL (Gamma-butyrolactone) Dubbed "coma in a bottle", it's a chemical solvent originally devised for use as a paint stripper. It has an ecstasy-like effect and is potentially very easy to overdose on as it comes in liquid form. It's also especially dangerous mixed with alcohol and has been associated with several deaths. As a class C drug, it's illegal to possess, sell or give away.
(2)BZP (Benzylpiperazine) A class C drug, it's made from piperazine, a de-worming agent for animals. It comes in pill form, has an ecstasy-like effect and can also cause seizures. It's particularly dangerous mixed with other drugs and alcohol.
(3)Spice This smoking mix contains compounds that mimic the effects of THC, the active ingredient in cannabis. Not much is known about its long-term effects yet but it's feared that it may carry the same risks of long-term psychotic illness as real cannabis. It's also illegal to have, sell or give away but because it's a class B drug (like cannabis), it carries tougher sentences.
By Miriam Stoppard
February 1, 2010
Why the latest party drug brings new dangers