“WHEN he first sees her, Raf is sitting on a washing machine about to swallow an eighth of a gram of what is apparently a mixture of speed, monosodium glutamate and an experimental social anxiety disorder medication for dogs.” So begins “Glow”, the latest novel by Ned Beauman, a British author. The scene captures a global reality: in much of the world, traditional mood-altering substances such as cocaine and heroin are in decline. But a pharmacopoeia of synthetic drugs is rapidly taking their place.

That is also the conclusion to be drawn from the latest report of the UN Office on Drugs and Crime, published on May 20th. By 2013, 348 new psychoactive substances had been reported to the agency, almost all of them since 2008 (see chart). They include 110 synthetic cannabinoids (which are supposed to mimic the effects of smoking marijuana) and many more little-understood stimulants. Between 2010 and 2012 seizures of older synthetic amphetamine-style drugs, mostly methamphetamine, or “crystal meth”, doubled, largely because of demand in Africa, Asia and South America.

In America and Britain, where the authorities conduct regular surveys of drug-taking, cocaine use has fallen steeply since around 2008. In most of Europe heroin addiction is becoming rare. Wholesale cocaine prices have risen sharply over the past decade, partly thanks to eradication efforts in Colombia and elsewhere squeezing supply, pushing up prices and hitting quality. In Europe much cocaine is now laced with levamisole, a cattle-deworming drug. Heroin, too, is pricier and of worse quality; some batches in Europe appear to have been infected with anthrax.

But such victories in the global drug war have been decidedly partial. Though most drug takers prefer traditional fare, says Fiona Measham of the University of Durham, who studies the drug-taking and drinking habits of young people, if they cannot get hold of it many will try other white powders, even unidentifiable ones. In 2010, when ecstasy (MDMA) was particularly scarce, 4.4% of British 16- to 24-year-olds tried mephedrone, an ecstasy-like drug, and 2.1% tried ketamine, a powerful tranquiliser used most often in veterinary medicine. One in nine Americans in their last year of high school now report having tried a synthetic form of cannabis. All of these were unknown a decade ago.

Mephedrone, which arrived in Europe around 2009, could be ordered online extremely cheaply from manufacturers in China who described it as “plant food” or “research chemicals”. It was quickly banned, yet consumption has continued. Dealers who used to sell ecstasy and cocaine now sell mephedrone, says Niamh Eastwood of Release, a British drugs charity. It has attracted heavy users, including some former heroin addicts, who inject it into their muscles up to 20 times a day.

Another drug with the wide appeal of mephedrone is yet to emerge, but hundreds more synthetic “legal highs” have appeared, manufactured by chemists who often share molecular diagrams and recipes online, and sold with weaselly labels reading “not for human consumption” or “novelty collector’s item”. New substances emerge and are banned so quickly that sellers may become illegal-drug dealers without realising it. They distribute their wares by post, typically in vacuum packages. This has helped change the market in traditional drugs, too. In Australia, where geographical isolation has long made it expensive to get high, drugs are increasingly being imported from Europe, sometimes by standard mail.

In parts of the developing world ketamine is the latest poison of choice. Among those imprisoned for drug use in Macau, 18% have used it, second only to methamphetamine. Seizures of ketamine in China made up almost 60% of the global total between 2008 and 2011. A recent survey of drug-taking among the young in Argentina suggests the drug may now be more popular than cocaine. There it is often labelled as ecstasy, as is LSD, which users in rich countries have all but abandoned.

In poorer countries methamphetamine remains the rage. In Central and South Asia it seems to be taking the place of heroin as the product of choice for drug gangs. Between 2011 and 2012 the quantity of methamphetamine seized in Myanmar more than tripled. In Iran seizures have climbed from almost nothing in 2005 to 4,000kg last year. Meth labs have even been found in Afghanistan, where the poppy crop has long sustained farmers. The pills go to a growing number of addicts in the Philippines and Thailand, as well as in Arab countries, where traditional amphetamines also remain popular.

Government attempts to crack down on one new drug after another bring to mind a game of whack-a-mole, says one expert. Each new drug brings new harms to users, too. Ketamine has proven far more addictive and physically damaging than ecstasy, and some synthetic cannabinoids have worse side-effects than real cannabis. And though their use still seems to be fairly limited, 52 people in England and Wales died in 2012 after taking new psychoactive substances, up from a handful a few years earlier. That is more than died after taking amphetamines or ecstasy.

Old war, new fronts

The production of new drugs is no less damaging. Mexican and Burmese gangs have diversified from cocaine to the production and sale of methamphetamine, and remain just as violent. In eastern Europe methamphetamine production has spread from the Czech Republic, where addiction to the drug has been a problem since communist times, to neighbouring countries, including Austria and Germany. Such trade routes are no easier to police than those that brought in heroin and cocaine. The number of Europeans treated for use of methamphetamine, though still small, is rising quickly.

In New Zealand, where synthetic drugs are particularly popular, the government has committed itself to testing and regulating new drugs, rather than banning them. So far the practical effect has been to ban all of them, as no testing regime is yet in place, which may be helping the illegal market. But the long-term aspiration is wise. Not all drug-taking is harmful, but trying to stop it has proved extremely so.