CANNABIS: STUDY DEMONSTRATES THE SCALE OF DRUG'S GLOBAL POPULARITY

It is 40 years since cannabis unleashed the "flower power" revolution
of the 1960s, encouraging a generation in Europe and the US to "make
love not war". Young people at the time hoped their legacy would be
world peace. Instead, it has turned out to be a world of fuzzy dope-heads.

In the intervening decades, the drug whose intoxicating effects have
been known for 4,000 years has been increasingly adopted by
adolescents and young adults across the globe.

Today, an estimated one in 25 adults of working age - 166 million
people around the world - has used cannabis to get high, either in
ignorance or defiance of its damaging effects on health. Now, the
extraordinary popularity of the drug is posing a significant public
health challenge, doctors say.

Writing in The Lancet, Wayne Hall of the University of Queensland and
Louisa Degenhardt of the University of New South Wales, Australia,
say cannabis slows reaction times and increases the risk of
accidents, causes bronchitis, interferes with learning, memory and
education and, most seriously, may double the risk of schizophrenia.
Yet these effects have failed to dent its popularity.

"Since cannabis use was first reported over 40 years ago by US
college students, its recreational or non-medical use has spread
globally, first to high-income countries, and recently to low-income
and middle-income countries," they say.

Citing figures from the UN Office on Drugs and Crime for 2006, they
say cannabis use is highest in the US, Australia and New Zealand
(where more than 8 per cent of the population indulge), followed by
Europe. But because Asia and Africa have bigger populations, they
also have the highest proportion of the world's cannabis users,
accounting for almost a third (31 per cent) and a quarter (25 per
cent) respectively.

Use of cannabis among young people rose strongly during the 1960s and
1970s, peaking in the US in 1979. There was then a long decline until
it increased again in the 1990s, before levelling off once more since
2000. In Britain, Australia and New Zealand, cannabis use has been
falling for several years, but it is thought to be rising in Latin
America and several countries in Africa.

The typical user smokes their first joint in their mid-teens, with
use peaking in the mid-20s. The habit then declines steeply as young
people move into jobs and discover they have to get up in the
morning. Marriage and babies accelerate the decline. About one in 10
of those who ever smoke a joint become regular daily users, with 20
to 30 per cent using the drug weekly. Regular users are also more
likely to use other illicit drugs, including heroin and cocaine,
lending support to the theory that "soft" drugs act as a "gateway" to
hard drugs. But the authors admit this supposed link "remains a
subject of considerable debate".

However, they add that the ill effects of cannabis are modest when
compared with the damage done by alcohol, tobacco and other illicit
drugs. In Australia, it accounted for just 0.2 per cent of the total
burden of disease.