Cannabis link to 80 per cent of new mental cases

By MATTHEW HICKLEY


Eighty per cent of patients newly-diagnosed with schizophrenia and other psychiatric illnesses are heavy users of cannabis, scientists have warned ministers.

The shocking figure emerged in a dossier submitted to Whitehall drug advisers as Gordon Brown weighs up whether or not to reverse Labour's "softly-softly" policy of downgrading cannabis. Campaigners have pointed to a flood of scientific evidence on the devastating damage the drug can do to mental and physical health.

Much of it has come in the four years since David Blunkett decided to reclassify cannabis from Class B to Class C, so that most users caught by police no longer face arrest or a criminal record. The Prime Minister ordered a review of that policy last summer following years of warnings that stronger "skunk" varieties of cannabis are wreaking havoc on users' mental health.

The Government's Advisory Council on the Misuse of Drugs will take evidence from leading academics next week before sending its latest official advice to ministers. Psychiatrist Professor Peter Jones, of Cambridge University, says in the dossier that eight out of ten newly-diagnosed psychiatric disorders affect heavy or dependent cannabis users.

He warns that children who are starting to smoke cannabis as young as ten or 11 could be trebling their risk of schizophrenia. Other new evidence of harm to mental health includes a UK study suggesting that by 2010 as many as 25 per cent of all cases of schizophrenia would be actually triggered by cannabis use. In a letter published in the Times yesterday, leading researchers and policy experts urged ministers to read the evidence and to toughen the law again.

A U.S. study found that smoking just half a cannabis joint could trigger schizophrenia-related symptoms.

Biologist Mary Brett of the Europe Against Drugs campaign, a signatory to the letter, said: "Every single piece of research around the world now emerging is bad news." A Home Office spokesman said: "We have always said that cannabis is an illegal and harmful drug. But to tackle drugs in the most effective way we need to monitor and review the ways in which we reduce the harm caused by illegal substances. That is why we are reviewing cannabis classification."

Source:http://www.dailymail.co.uk/pages/live/articles/health Jan 2008