Cost of cannabis use 'overlooked'

Cannabis will be classified as a class C drug from 29 January

The indirect dangers of cannabis use and their potential costs have been largely overlooked by policy-makers, according to new research.

An Economic and Social Research Council study found 74% of users had driven and 25% had worked after taking cannabis.

The study looked at 100 regular and 90 casual users ahead of the downgrading of the drug from class B to class C.

The Home Office said it had looked at the wider effects of cannabis and it would remain illegal after the change.

A spokeswoman said the downgrading did not mean they were telling people to now take the drug.

She pointed out that a report by the Advisory Council on the Misuse of Drugs said that "cannabis impairs the performance of complex tasks that require sustained attention and motor control".

Previous studies

Researcher Dr Philip Terry from the University of Birmingham said: "Much effort by policy-makers has been directed towards identifying potential health problems that might result from cannabis use."

He said previous studies had failed to examine the extent to which chronic use of cannabis was likely to increase someone's risk of accident or injury, or to have potentially significant adverse effects on their financial or social well-being.

The study found cannabis use before and during sex was reported by 87% of users with 10% saying this made them less likely to use a condom, putting them at risk of sexually transmitted diseases.

Users were also more likely to take other drugs - 40% reported using other illegal substances, mainly cocaine and ecstasy, it said.