Quarter of Scots aged 15 have tried cannabis

Ten per cent of Scottish 15-year-olds regularly smoke dope and more than a quarter have experimented with the drug, a major new study has found.

The report, which is supported by the World Health Organisation, examined the lifestyles of 6,000 pupils aged 11, 13 and 15 in March 2006.

The Prime Minister has indicated he wants to toughen the law on cannabis. It was weakened in 2004 but many experts believe it sent out the wrong message to young people.

The availability of skunk – the strongest form of cannabis – has soared since the law was weakened. According to Home Office research, it now accounts for between 70% and 80% of samples seized by police, compared with 15% six years ago.

Alistair Ramsay, the former director of Scotland Against Drugs who now runs a drugs advice company said: “There were a number of recent studies from New Zealand where they looked at the implications of cannabis on the brains of young people.”

“They found there was long-term damage done to the brains of young people if they started too young,” he added.

Marjorie Wallace, of mental health charity Sane, has said that young people using cannabis regularly “can double their risk of developing schizophrenia, in which a person may hear voices, and experience strange thoughts and paranoid delusions.”

Professor Louis Appleby, the National Director for Mental Health at the Department of Health, said in February: “We have become complacent on cannabis, based on concern about how widespread it is and some scepticism if it is generally harmful. That complacency has to come to an end.”

A study lasting 27 years involving 50,000 people showed that smoking cannabis trebles the risk of a young person developing schizophrenia.

Cannabis-related admissions to mental hospitals have risen by 85% since Labour came to power according to Government figures.

There are now more than 22,000 people a year, almost half under the age of 18, being treated for cannabis addiction. In 1997 the number was 1,600.