The British government has just ushered in a new age of prohibition, by introducing a blanket ban on all so-called psychoactive drugs. The new bill, which was first proposed last year, comes into force today following a series of delays caused by a lack of understanding over which substances are actually covered by the controversial legislation.

Known as the Psychoactive Substances Act (PSA), the new law has been brought in as part of the government’s attempts to clamp down on new psychoactive substances (NPS), also called “legal highs”. These are drugs that are designed – often in laboratories in China or India – to replicate the effects of illicit substances, yet which themselves have not been outlawed because they are too new.

Legal highs such as mephedrone began to flood UK markets from around 2008, drawing the government into a game of cat-and-mouse as it struggled to keep up with all the NPSs, which were being created faster than the authorities could ban them.

With the PSA, however, the government hopes to solve the problem with one fell swoop, effectively checkmating distributors of legal highs by banning any substance capable of producing psychoactive effects.

Yet many have accused the authorities of taking a sledgehammer to a situation that required a scalpel. For instance, president of the European Brain Council Professor David Nutt recently told IFLScience that the new bill is “anti-scientific,” as by banning all psychoactive substances it essentially handcuffs researchers working with certain mind-altering drugs that could have therapeutic potential.

Furthermore, scientists and politicians have struggled to agree on the definition of a psychoactive substance, as well as which drugs should be exempt from the bill. In theory, a law banning all such chemicals should mark the end of legal sales of booze, cigarettes, and coffee. Given that those who flout the PSA could face up to seven years in jail, this seems a high price to pay for your morning cappuccino.

^{After much debate, laughing gas has now been banned. IanRedding/Shutterstock}

The government has therefore drawn up a list of substances that will not be outlawed – including alcohol, caffeine, and nicotine, as well as certain medications. As for those not specifically mentioned on this “white list,” the law remains somewhat hazy and open to interpretation. For instance, following recent debates, it was decided that poppers could not be banned by the PSA as they stimulate the peripheral nervous system rather than the central nervous system.

Among the chemicals definitely banned, however, is nitrous oxide – otherwise known as laughing gas. Something of a poster drug for the campaigns both for and against this new legislation, the gas has been at the center of the issue ever since the debating began, with both sides accusing the other of mistaking the drug’s safety profile. Yet with all now said and done, fans of nitrous oxide are going to have to find other things to laugh about.