Rob Ford, mayor of Toronto, Canada, caused a sensation last week when he told journalists, “Yes, I have smoked crack cocaine” — and refused to resign. The reporters smelled blood: Ford had long denied drug use, despite repeated rumours. “I wasn’t lying,” he said when confronted. “You didn’t ask the correct questions.”

The debate over the control and regulation of drugs is typified, perhaps more than any other in science policy, by a need to ask the correct questions. Politicians and the moralizing media tend to seek the black-or-white certainty of whether or not a drug poses a threat. Researchers often prefer to present risks as relative, and some argue that it is hypocritical to proscribe one compound while promoting, however tacitly, the consumption of another that may have similar — or more potent — effects.

From time to time the answer changes because of other factors, and this is where the question becomes less important than who is asking it. The television drama Breaking Bad has brought the abuse of methamphetamine to popular attention, but the government of Japan, for example, has long been well aware of the drug’s effects. In fact, during the Second World War it encouraged the manufacture of the compound and distributed it to the country’s soldiers and civilian workers in a handy tablet form called hiropon. “For night work and other times demanding mental alertness. For overexertion,” a typical wartime advert read. “The most powerful new amphetamine on the market!”

At the end of the war, Japanese manufacturers sold the stimulant as a cure for all manner of civilian ills, targeting, among others, juveniles disturbed by the country’s dramatic post-war social change. Yet within a few years, a government U-turn introduced tough laws making the drug illegal, with harsh penalties for possession. Official propaganda now called on citizens to help the authorities to “wipe out the evil of stimulant drugs!”. Widespread abuse and signs of addiction gave the authorities a legitimate reason to act. But, as historian Jeffrey Alexander of the University of Wisconsin–Parkside pointed out in a paper this year (J. W. Alexander Int. J. Drug Policy 24, 238–243; 2013), there was another, more sinister motive: the deliberate cultivation of a media-fuelled drug panic to justify the arrest and deportation of Korean and Taiwanese immigrants, who were disproportionately blamed for making and selling methamphetamine.

Similar social pressures played a part in the crafting of US legislation against marijuana, which was first popular with Mexican labourers and black musicians. Prejudice is one of a number of issues contributing to policies on drugs that are explored by two books reviewed by Andrew Robinson on page 194. The books explain, he says, that “a drug’s acceptability to mainstream society fluctuates more owing to social and cultural trends than to medical knowledge”. For example, the United States infamously banned alcohol during the prohibition era of the 1920s and 1930s, a move that would have been unlikely in the United Kingdom because of the “complex British attitude to drunkenness”.

This attitude was highlighted in 2009 by the UK government’s then-drug adviser David Nutt, who argued publicly that alcohol and tobacco were more harmful than LSD, ecstasy and cannabis. His opinion earned him the sack. Last week, it also earned him the 2013 John Maddox Prize for Standing Up for Science, which recognizes the promotion of science in the public interest, and was set up with the help of this publication. Someone has to keep asking the correct questions.