This article is more than 11 years old

This article is more than 11 years old

The revelation that students at the country's most prestigious seats of learning enjoy an occasional joint is hardly the stuff of headlines - unless that country is Japan.

Judging by recent coverage, Japan is in the midst of a marijuana epidemic that is ensnaring everyone from students to suburban housewives and sumo wrestlers.

A slew of arrests for drug-related offences among elite scholars has sparked widespread indignation that more youngsters are choosing to while away their university years in a fug of marijuana smoke.

While police once focused their attention on amphetamines and other stimulants, recent statistics show a dramatic increase in cases involving cannabis. In the first half of this year the number of cases in which suspects were questioned or arrested stood at 1,202, a 12% increase on the same time last year. The number of cases involving the cultivation of cannabis at home was up by almost 50%, the national police agency said.

A record 2,423 violations were recorded in 2006, but police expect that figure to be beaten with ease this year.

Recreational marijuana use hit the headlines this summer when three Russian sumo wrestlers were kicked out of the sport for allegedly smoking the drug. In recent months newspapers have reported arrests for dealing, cultivating or possessing marijuana at some of Japan's best universities.

Daytime TV shows, meanwhile, blame foreign suppliers for corrupting gullible Japanese teenagers and, increasingly, bored housewives, as they move out heavily policed city centres into the suburbs.

The Mainichi Shimbun, often a progressive voice on other issues, devoted part of its front page yesterday to a fuming editorial warning of the potential ruination of Japan's finest universities by the evil weed.

Noting that students of the 1960s concerned themselves only with "world peace", the paper derided their modern-day counterparts' unhealthy obsession with attaining a different kind of tranquility.

Of the recent campus arrests, it says: "It is rational to believe that these cases are just the tip of the iceberg, and that 'drug pollution' at university campuses is more widespread than generally thought."

There does not appear to be a problem with supply. In July, police in Tokyo seized 180kg of cannabis - Japan's biggest haul - with a street value of ¥720m (£4.6m).

Smokers who prefer not to risk buying from dealers - who charge, on average, six times the going rate in the Netherlands - are growing their own. Accordingly, the number of people arrested for growing the plant at home, many with seeds bought on the internet, has risen fivefold over the past 10 years.

Japanese law takes a dim view of the recreational use of soft drugs. The 1948 cannabis control law calls for prison terms of up to 10 years and hefty fine for anyone found importing, exporting, growing, selling or buying cannabis.

Its use for medical purposes, permitted in some other countries, is also banned.

Japanese activists are pushing for a change in the law to permit the use of cannabis among sufferers of diseases such as cancer, multiple sclerosis and Parkinson's.

"Cannabis is harmless compared to alcohol and tobaccos, but still the government overreacts and ruins the lives of anyone found with it," Koichi Maeda, the founder of the Japan Medical Marijuana Association, told the Guardian. "We asked the government to provide evidence of the harm they say marijuana causes, but they couldn't."

Maeda, who runs a hemp restaurant in Tokyo, believes recent media coverage of the issue shows how far public attitudes towards dope smoking in Japan lag behind those in Britain and parts of Europe.

"The authorities use the media to peddle their claims that marijuana is a gateway drug to harder substances, and the media are too stupid to check if what they are being told is true," he said. "All the newspapers do is run sensationalist articles based on what the police tell them. It makes me so angry.