CANNABIS - MEDICINE OR MENACE: Prof Philip Murphy

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When someone says they are taking black market cannabis to help with health problems, Prof Philip Murphy likens it to “a bit like pouring yourself a glass of whisky for medicinal purposes”.

Prof Murphy, who is head of psychology at Edge Hill University, has worked professionally in drug misuse since 1984 and has carried out extensive research into how the misuse of cannabis and ecstasy impairs cognitive performance such as memory and its effect on mood disturbances.

Professor Philip Murphy, head of psychology at Edge Hill University

Professor Philip Murphy, head of psychology at Edge Hill University

However, although he against the legalisation of cannabis and its use recreationally, he believes there is political confusion which has hampered it being used to produce beneficial medication.

He explains: “I am opposed to the legalisation of cannabis. But I am perfectly happy to see cannabinoids prescribed as medication. I think there is confusion surrounding this at a political level.

“There is a fear among politicians that they will be seen to have legalised cannabis.”

Prof Murphy says cannabis is comprised of more than 400 compounds and around 60 of these are regarded as active cannabinoids.

He explains that pharmaceutical preparations of cannabinoid medications will have carefully selected the clinically beneficial cannabinoids for a given condition requiring treatment.

As a result, he says clinically prescribed cannabinoid medications bear very little similarity to black market cannabis.

Prof Murphy says: “Such preparations have been designed for administration by routes other than smoking such as tablets and sprays.

“When you extract the therapeutic compounds of cannabis – notably one known as CBD which has a number of very powerful medicinal applications – you are talking about something very different from the black market supplies of cannabis bought in pubs or on street corners.

“It is the difference between a properly produced pharmaceutical product and something in its raw form.

“I cannot see any logical argument against the use of a pharmaceutical preparation involving cannabinoids.”

Prof Murphy has done a lot of work looking at the negative effects of cannabis when used recreationally and has found it impairs memory performance, makes the brain work harder to maintain the level of performance of non users and is linked to episodes of psychotic behaviour, especially where a predisposition to psychotic episodes exists.

Prof Murphy says: “There is evidence cannabis can impair memory functioning, can change the levels of activity in the brain which suggest the brain has to work harder to match the performance of a non-user on some laboratory tasks and that some black market preparations very high in concentrations of a cannabinoid known as THC can lead to psychotic episodes in people with a predisposition to such episodes.

“With recreational cannabis users, I have found cannabis to be a very dependance producing drug.The main psycho active compound of cannabis is THC. THC levels in the days of the hippies were one to two per cent.

“However, today, particularly in skunk cannabis, THC levels can be 20 per cent or even more.

“People say cannabis is not addictive, but that is now an outdated view as cannabis has changed so much from what it used to be.”

Despite knowing the negative implications of cannabis, Prof Murphy says it is perfectly possible to have a drug made using cannabinoids and available by prescription only.

He explains: “Carefully manufactured pharmaceutical preparations need to be prescribed by qualified clinicians in a context of professional clinical management.

“Cannabis should not be legalised for recreational use and open sale.

“This does not logically contradict its appropriate use in treating illness and curbing suffering.

“Sadly, it is likely that political considerations around a fear of having been seen to have legalised cannabis may have retarded the development of cannabinoid based medications.

“This is very unfortunate and likely to have perpetuated suffering for some people unnecessarily.

“All the work I have done on illegal cannabis affecting memory still holds true.

“But as with any other medication, we have to hold potential problems in consideration against the potential benefits.

“That is for the clinician treating the patient to do as they would with any other medication.

“There are negative effects to every medication. It is about balancing the benefits against the potential risk.”