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.
Source - Daily Mail