'Legalise It, Don't Criticise It' - Should Cannabis Be Legalised?

04/07/2013 17:19 BST | Updated 03/09/2013 10:12 BST

The above lyrics are taken from a Bob Marley song which has been covered by UB40 entitled Legalise It; arguing for the legalisation of cannabis. The issue of drug use has been discussed recently due to critics arguing that events such as Glastonbury promote the culture of illegal drug taking. I can picture many of you, who are perhaps a bit naive when it comes to drug use reading this with a look of disgust on your face, but let's just consider the facts for a moment before we jump to the conclusion that if cannabis is legalised the UK will become a massive drugs ghetto with tens of millions of people suffering from mental health issues such as schizophrenia.

One argument against the legalisation of cannabis is the 'evidence' which links the use of cannabis to the development of schizophrenia. Please note that I use the word links and not causes - This is very important as I hope I will be able to explain. Even the most hard-line right wing so-called experts in mental health will admit that only a small proportion of schizophrenia cases can be accounted for by the use of cannabis. Yes, unfortunately the majority of cases of schizophrenia can be accounted for by genetic factors, brain development disorders and chronic stress.

So, why are certain groups so convinced by the evidence that cannabis can cause schizophrenia? First we need to understand the neurological basis of schizophrenia (don't worry I will not get too technical here): Schizophrenia is caused by an imbalance in a neurotransmitter called dopamine, particularly in the frontal-lobes and limbic system of the brain. If you give a person with schizophrenia drugs which increase dopamine across the whole brain, their symptoms worsen. Specifically, people with schizophrenia show a decrease in dopamine levels in the frontal cortex of the brain and an increase in dopamine levels in the limbic region of the brain which is responsible for many functions including addiction (Rogers, 2001).

Smoking tobacco releases nicotine which stimulates the release of dopamine in the frontal cortex of the brain, therefore there is no surprise that there is a very high correlation between smoking and schizophrenia. Here comes the uncomplicated part: drug dealers tend to target younger adults who smoke. These drug dealers begin with selling cannabis before pushing other more dangerous drugs to the buyer. These drugs tend to begin with ecstasy and LSD, then build up to coke and if the person is really unlucky heroin.

I can hear all my anti-drug campaigners screaming out 'See cannabis does lead to people taking harder drugs!' No, that is simply only because cannabis is illegal. Believe it or not, one does not have a joint or chocolate brownie and then thinks 'Ooh, I will take some crack cocaine tomorrow.' The majority of people who enjoy cannabis do not want any other drugs such as ecstasy, speed or coke, because these are uppers (drugs which excite you and give you more energy; and definitely do not help you relax). Cannabis on the other hand is similar to alcohol in that people who take it mainly do so to help them relax.

So, how about the quality of the cannabis which you get from your local dealer? Unfortunately if you smoke resin you will find that quite a lot of that little black block is made up of tarmac, plastic bags and even dog excretions (lovely!). If you smoke skunk then the probability is that you have a lot of stuff which is a nice green or yellow colour which will burn in it. This includes nylon carpets, a number of herbs (excuse the pun) and anything else which the dealers can get hold of to spread out their packet of dope which you are buying. Yes, unfortunately the cannabis which is available on the street is probably only 40 to 50% cannabis if that.

Let's reconsider the argument for the relationship between cannabis and schizophrenia; is it at all possible that the rubbish that dealers use to make the cannabis go further causes damage to the brain? I don't think inhaling plastic bags, dog poo or nylon carpet does anyone any good. There is also the case that the dealers will push other drugs onto the buyers, and it is well known that cocaine and drugs like that have a massive effect on dopamine in the brain. We are also forgetting the relationship between smoking and schizophrenia; even when the schizophrenia has not become apparent these people tend to smoke more, just they are targeted by the drug dealers and a lot of drug dealers are not the kind of people you would take home to meet your mother. A lot of drug dealers are also associated with money lending and organised crime and if a person who has a genetic predisposition to schizophrenia becomes entangled in this the only result is an increase in stress, which brings on the schizophrenia.

Okay let's lay off the friendly dealers for a moment and look at this in a different perspective. If cannabis was legalised, then the government could control the strength of the drug and users would know what they were taking. This is the case in the Netherlands where cannabis is legal; you can eat it, drink it in tea or smoke it in a joint; but you know what kind you are having and how strong it is in terms of THC (the active ingredient in cannabis which stimulates dopamine and GABBA-a release in the medial temporal lobe and brain stem). Now if cannabis causes schizophrenia one would expect a higher rate of schizophrenia in the Netherlands compared to the UK where cannabis is illegal. Whoops, that is not the case according to a report by the World Health Organisation; in 2004 the WHO calculated the disability-adjusted life years for all countries and reported the diagnosis of both physical and mental illnesses per head of the population. For schizophrenia, we are looking on a scale from the lowest, which was Australia with 164.225 per 100,000 to the highest, Indonesia that has 321.870. So let's compare the cannabis smoking Dutch to the stiff upper-lipped British; the Netherlands had 168.282 while in the UK the diagnosis of schizophrenia per 100,000 was 185.182. You do not need to be a mathematical genius to see that where cannabis is legal and regulated the diagnosis of schizophrenia is lower than where it is not regulated and illegal.

Finally, let's consider the number of deaths caused by legal drugs compared to cannabis. According to national statistics in 2011 just below 8,750 deaths were the direct cause of alcohol. If one would like to read, 100,000 died from smoking every year. How many died directly from cannabis overdose? The answer is a big fat 0! It is physically impossible to overdose on cannabis. Furthermore it is physically impossible to become addicted to the active ingredients of cannabis because THC has such a long half-life that you do not become physically dependent upon it unlike alcohol and nicotine. Yes, okay you can become psychologically addicted to cannabis, but you can also become psychologically addicted to anything from alcohol to chocolate (regardless of whether it is legal or illegal). There is also the cost of alcohol and smoking on the NHS; according to the Daily Mail alcohol abuse costs the NHS £6billion a year, and according to the BBC news smoking costs the NHS £5 billion a year. It is true that schizophrenia costs the NHS £6.7billion a year, according to NICE (but only a tiny amount of this can arguably be the direct result of cannabis, if any at all).

Professor David Nutt lost his job for suggesting legalising cannabis; but if the former chair of the Advisory Council on the Misuse of Drugs does not know what he is on about then there is something wrong. Sure, many of you will be moaning that if cannabis is legalised then we are advocating smoking; that does not have to be the case, for example you could legalise cannabis for the consumption in food and drink in cafes for individuals who are aged 18 and over. The tax revenue which we would raise from cannabis could be used to treat schizophrenia, educate children on the misuse of drugs and help to reduce the Government's deficit. Let's face the truth, the USA had to end prohibition due to the fact that the sale of illegal alcohol was massive and funding criminal organisation, as well as killing hundreds of people with highly toxic beverages such as moonshine; so when are we going to get a grip and legalise cannabis... and relax?