Gone to pot: With our country looking at legalisation, it’s time to have a serious discussion on the effects of marijuana

Sleepwalking into a liberal regime which will legalise cannabis is how a group of senior psychiatrists recently described the present situation in Ireland.

The group, calling itself the Cannabis Risk Alliance, courageously expressed its concerns now the Government is considering decriminalising cannabis use. The group consists of substance misuse experts, professors who specialise in psychosis, clinicians who work day to day with young drug abusers, and researchers in the area.

Surprisingly, those who favour medicinal cannabis were concerned about the psychiatrists' comments. But less surprising were the sardonic comments in 'Hot Press' a few days later dismissing the concerns as "the return of reefer madness".

There are two principle constituents in the cannabis plant. Tetrahydrocannabinol (THC) is marijuana's main mind-altering ingredient. Cannabidiol (CBD) is of interest in treating certain conditions, such rare cases of childhood epilepsy. This does not have any mind-altering properties and a licence has been granted for use in individual cases. It is available as a tablet or spray. There is little concern about CBD from a psychiatric perspective, provided this is closely monitored. On the other hand, THC is associated with psychosis, low mood and a number of behavioural and mental disorders which cause grave worry to psychiatrists.

The terminology can be confusing. Medicinal cannabis refers to the use of cannabis of the CBD variety for specific severe illnesses such as cancer-induced pain, muscle spasm in neurological conditions and a rare form of epilepsy. This aspect is the easiest to deal with, both on compassionate and scientific grounds, since there will be defined outcomes which can be measured. However, if medicinal cannabis is to be licensed it should be done through the Health Products Regulatory Authority, which oversees all medicines, and not via a special bill known as the Medicinal Cannabis Bill.

The second term, decriminalisation, refers to not criminalising those found in possession of small quantities of cannabis for personal use but still penalising those who grow it. This variety will contain THC, the ingredient linked to psychosis. This is the proposal coming before Cabinet. The Cannabis Risk Alliance sees this as "a Trojan horse" towards full legalisation and commercialisation. Shine, the organisation which supports and educates those with psychosis, has come out to support the alliance.

The third term, legalisation, is the most popular among cannabis promoters. This approach would allow it to be used by our citizens and grow-factories would be controlled by law. The producers would pay taxes, the economy would benefit while the drug barons would move out of the cannabis business, according to the campaigners. The Netherlands, the first country in the world to legalise cannabis, is now hearing calls to legalise other drugs such as heroin, cocaine and ecstasy. The "slippery slope" argument comes to mind.

There is little doubt there is a softening-up process in train in Ireland. Already politicians are speaking of us being able to produce our own supply of medicinal cannabis. The discussion, even before it has started, has moved from the medical to the economic arena. Campaigners argue that other legal drugs such as tobacco and alcohol are more dangerous.

Have we forgotten that we had our own cultural flirtation with drug legalisation in 2009, when a legal loophole was found which allowed for the sale of synthetic psychoactive substances? The infamous "head shops" mushroomed across the land, while those of us working in hospital emergency departments experienced a huge increase in the numbers presenting with psychosis. Some were new patients who had never been ill, others were already under treatment and their use of these substances destabilised their illness. When they were reprimanded, they would retort "but these are legal, doctor".

Several aspects of cannabis concern the Cannabis Risk Alliance and supporting organisations. One is that it may cause psychosis. While the causal link is disputed by pro-cannabis campaigners, several facts have been proven. The younger the onset of cannabis consumption and the more frequent the use, the greater the risk of psychosis. Only a few weeks ago, a study from King's College London and published in 'The Lancet Psychiatry' found that among 11 sites in Europe and South America, London had the highest rate of psychosis overall and Amsterdam the highest rate of cannabis-induced psychosis. These cities happen to have the highest rates of overall consumption in Europe.

The researchers concluded smoking cannabis daily tripled the risk of developing psychosis. They also calculated that if the stronger strain, skunk, was no longer available, the rate of psychosis would drop from 46 to 32 per 100,000 per year. The findings come as no surprise to those at the coal face of psychiatry.

Two other domains of concern exist. The first of these relates to road traffic accidents, particularly fatalities. Studies conducted in the US states which have legalised cannabis show an increase in fatalities in the year or so after legalisation but then a decline to pre-legalisation levels. A study from Monash University suggests initially cannabis and alcohol may be combined and that, over time, alcohol is replaced by cannabis, causing a levelling effect.

Finally, there is the cancer debate. Marijuana contains more carcinogens such as benzpyrene and benzanthracene than those found in unfiltered tobacco smoke. However, lung cancer does not appear to have increased in those who have smoked "weed". At this point, the wise approach is to say we don't know.

Our Government has a duty to us to act judiciously, listen and engage in research, instead of being driven by vested interest groups.

Irish Independent