According to a new report by a British government advisory body, the regular use of cannabis though it can have real and significant mental health effects it is unlikely to cause schizophrenia.

Government drugs advisers in the UK say cannabis can impair psychological and physical performance, cause acute intoxication reactions and prompt relapses in individuals vulnerable to mental illnesses.

The Advisory Council on the Misuse of Drugs says that based on current evidence smoking cannabis was likely to increase the chances of developing schizophrenia by just one per cent.

Cannabis is currently a Class B drug in the UK and the council, had been asked to reconsider the Government’s decision to downgrade cannabis from a Class B to a Class C substance.

The council in 2003 had recommended that cannabis should be downgraded, and was asked by ministers to look again at medical evidence suggesting that more powerfully psychoactive varieties of the drug were posing an increased danger to mental health.

The committee now believes the drug should be downgraded as evidence suggests, at worst, that using cannabis does not significantly increase the lifetime risk of developing schizophrenia.

They say that while cannabis can, unquestionably, be harmful it is not of the same order as those of substances within Class B.”

The council says that since 2003 further evidence has emerged about the possible link between the use of cannabis and the subsequent development of psychotic symptoms.

However, the council emphasised that cannabis use was harmful, it can cause bronchitis and cancer and should be discouraged.

The council wants to see “a sustained education and information strategy” and more research into the links with mental health problems.

British home Secretary Charles Clarke, has confirmed that he proposes to keep cannabis as a Class C drug, which means police generally take a more lenient line with personal possession and penalties are lower.

Mr Clarke says that though he was not about to reclassify cannabis, the message had to go out that it is nevertheless harmful and it can lead to a wide range of physical and psychological hazards.

He has ordered a review of the classifications system which dates to 1971 and many consider confusing and misleading, and is also examining the classification of the so-called “date-rape” drugs Rohypnol and GHB, which are currently Class C substances.