Is Cannabis Bad for Me? The Science... and How It Is Misinterpreted

13/12/2013 18:40 | Updated 12 February 2014
  • Marek Doyle Nutritional Therapist and Champion of Common Sense

A lot can be said for cannabis. And, as Uruguay approves the production and distribution of the plant, you can be sure you'll be hearing a lot more on the issue.

My own viewpoints on the herb were sculpted through work with a Californian client who, at the end of our second appointment, innocently asked me: "What do you think about cannabis?" I had surprisingly little information to offer her. After all, as an illegal substance in the country I lived in, I had not invested time in researching its safety or its medicinal benefits. When this question forced me to do so, Pandora's box was well and truly opened. I was shocked at what the evidence actually indicated.

Like everyone else, I knew that cannabis is bad for us, damages our minds and causes untold social harm. There's just one problem: the evidence says the exact opposite. Perhaps the entire saga can be paraphrased up by focusing on just one recent paper, a 2013 review by scientists from Pittsburgh. Entitled Medical Consequences of Marajuana Use (1), it is the go-to paper for anti-cannabis zealots. It is currently quoted regularly as evidence to support tightening the regulations on the herb.

The claims made on the back of this (and similar papers) are enough to scare most parents into instantly giving 'the drugs talk' to their teenage children and enough for the more neurotic to vote for whichever politician promises harsher penalties on cannabis distribution. This is, naturally, the aim for the conservatives, who quote the paper to demonstrate how cannabis can increase cancer risk, compromise cardiovascular health and damage the brain. And so on.

The thing is, I actually read the scientific papers. And herein lies the problem; the paper does not make these conclusions at all. What of that increased cancer risk? It concludes that there 'may' be an increased risk of cancer from those that roll up regularly, but not when you control for tobacco use. In layman's terms: cannabis only increases cancer risk when used with tobacco. That's more than a technicality, right there!

So what about the links to heart health? Reviewing a number of studies that searched for a cannabis-CVD link, the scientists determined that studies were conflicting although all studies agreed that long-term mortality was unaffected by the herb. No outcome either way.

But does it cause psychosis? Will your teenage son lose his mind if he blazes up? Here, the researchers acknowledge studies showing how marijuana use changes brain activation patterns, short-term concentration and co-ordination. Nothing ground-breaking here. However, they then pose the question of whether cannabis can affect a person's ability to learn after long-term use. They concluded that the heaviest users may have a decrease in their ability to learn and remember information, but that this effect was so small as to be 'acceptable'.

For a paper that is held up as a nail in the herbal coffin, it says very few negative things about cannabis. In fact, the scientific abstract features the unforgettable quote: "literature suggests that marijuana can cause physical harm. However, evidence is needed." I could not have put it better myself.

While I have highlighted just one research paper, many others follow this well-trodden path. Yet, regardless of how many billions are spent trying to prove cannabis is bad for us, and regardless of how much spin conservative politicians put on the issue, the anti-cannabis lobby is taking to the witness box with an embarrassing lack of evidence.

Meanwhile, an ever-increasing number of studies continue to highlight the blistering array of medical benefits that the plant affords; in recent years, we have learnt how the herb can protect against neuro-degenerative diseases (2) (3) (4), reduces risk of diabetes (5), helps to manage ADHD (6), improves glaucoma (7) and reverses multiple sclerosis and other autoimmune conditions (8). Impressive stuff.

I find it particularly amusing that the US government has accidentally funded more than it's fair share of studies that support the position of pro-cannabis activists. Despite trying to suppress such conclusions from entering the public domain, American tax dollars have taught us that:
cannabis is the only valid option for patients suffering from pain and wasting in chronic conditions such as AIDS (9)
cannabis may be useful in preventing cancer (10) (11) (12) (13)
cannabis does not promote a 'gateway' effect towards other illicit substances (14)
cannabis does not impact on long-term physical or mental health (15)
cannabis has no impact on mortality (16)

Now cannabis is not a panacea and, like other herbs, is not suitable for all individuals (for example, it's immune-altering effects can be incredibly helpful for sufferers of MS but can cause problems for those with regular infections or allergies). However, the scope of this post is not how best to harness the plant therapeutically, but to highlight how people rarely consider the facts for themselves, choosing instead to absorb the 'party line' without criticism. Intelligence appears to offer little defence against such habits, with many otherwise-insightful practitioners falling victim to dogma and propaganda. It remains quite ironic that, for a mind-altering herb, so many of us remain so close-minded to the facts.

References: for a full list, see here.