Significantly more people have been diagnosed with psychosis and schizophrenia since the law on cannabis was relaxed in 2004, figures released by the Government show.
In 2006-7, there were 213,624 cases of psychosis diagnosed, compared with 176,776 the year before the law changed. Similarly, diagnoses of schizophrenia were up from 40,763 in 2003-4 to 45,955 in 2006-7.
The statistics were published by the Department of Health in answer to a written parliamentary question from Conservative MP Graham Brady, who said they were “shocking”.
They come in advance of a report expected on Monday from the Government’s drugs watchdog, the Advisory Council on the Misuse of Drugs (ACMD) which will make recommendations on the legal classification of cannabis.
Mr Brady said: “Never before has the link between cannabis and mental illness been so clear,” he said.
“This makes a compelling case for the classification to be increased.”
Mental health experts have in recent months been highly vocal in denouncing the decision to downgrade cannabis from a class B to a class C drug because of its links to mental illnesses such as schizophrenia.
The figures will help bolster arguments to tighten up the law on cannabis so that possessing and dealing the drug would invite much harsher penalties.
Although leaks to the media suggest that the ACMD will not recommend a stricter law, recent indications have suggested that the Prime Minister is keen to return cannabis to class B.