Written question asked by Lord Brady of Altrincham (Conservative) on Tuesday, 21 October 2003, in the House of Commons. It was due for an answer on Wednesday, 29 October 2003. It was answered by Melanie Johnson (Labour) on Wednesday, 29 October 2003 on behalf of the Department of Health.

Dept of Health

Question: To ask the Secretary of State for Health, what assessment he has made of the relationship between the incidence of psychosis and cannabis use. - Includes ref to The Advisory Council on the Misuse of Drugs report "The classification of cannabis under the Misuse of Drugs Act 1971" and "Dangerous of Drugs - a Guide to the Risks and Harms associated with Substance Misuse".

Answer: Mr. Brady: To ask the Secretary of State for Health what assessment he has made of the relationship between the incidence of psychosis and cannabis use. [134347] Miss Melanie Johnson: The Department monitors research into the effects cannabis has on mental health on a continuous basis. The Advisory Council on the Misuse of Drugs (ACMD) published a report in March 2002--"The classification of cannabis under the Misuse of Drugs Act 1971"--in which it described the range of harms caused by cannabis, including its known effects on mental health. There has been a lot of debate about the use of cannabis and whether it can lead to mental illness, especially schizophrenia. No clear causal link has been proven for the latter, although recent epidemiological research has shown a stronger association than previously evident. Cannabis use can unquestionably worsen existing schizophrenia (and other mental illnesses) and lead to relapse in some patients. In addition, on 29 September 2003, the Department published "Dangerousness of Drugs--a Guide to the Risks and Harms associated with Substance Misuse", which outlines the chronic and acute problems associated with a range of licit and illicit substances commonly used in the United Kingdom, including cannabis.

Secondary information