How Safe Is Weed?

When it comes to marijuana, we don’t know. We don’t seem to have any reliable scientific research about the effects of weed. As the nation dives headfirst into legalization of marijuana, we should know more. We don’t. All we know is that Justin Trudeau's Canada is leading the march toward legalization... and that should cause us to have some serious doubts.

Writing in The New Yorker Malcolm Gladwell aims to be judicious in his appraisal of the research. In many ways it raises as many questions as it asks. (Via Maggie’s Farm).

Gladwell sums up the results of recent research:

A few years ago, the National Academy of Medicine convened a panel of sixteen leading medical experts to analyze the scientific literature on cannabis. The report they prepared, which came out in January of 2017, runs to four hundred and sixty-eight pages. It contains no bombshells or surprises, which perhaps explains why it went largely unnoticed. It simply stated, over and over again, that a drug North Americans have become enthusiastic about remains a mystery.

And yet… a recent peer-reviewed study, published in the Journal of Neuroscience, suggests that adolescents, people whose brains have not developed fully, incur a risk when they smoke weed. Even in seemingly small quantities weed can change the structure of the adolescent brain. Of course, as Gladwell notes, these studies do not often factor in the different kinds of weed and the different concentrations of certain chemical compounds. It's devilishly difficult to do a scientific study when the substances being tested are anything but identical.

The Daily Mail has the story:

Just one or two joints is enough to change the structure of a teenager's brain, scientists have warned.

And the drug could cause changes affecting how likely they are to suffer from anxiety or panic, according to a study.

Researchers found 14-year-old girls and boys exposed to THC – the psychoactive chemical in cannabis – had a greater volume of grey matter in their brains.    

This means the tissue in certain areas is thicker, and it was found to be in the same areas as the receptors which marijuana affects.

Experts said thickening of brain tissue is the opposite of what usually happens during puberty, when teenagers' brain matter gets thinner and more refined.

And also:

Researchers from the University of Vermont scanned the brains of teenagers from England, Ireland, France and Germany to study marijuana's effects. 

They found differences in the volume of grey matter in the amygdala and the hippocampus.

These sections are involved with emotions, fear, memory development and spatial skills – changes to them suggests smoking cannabis could affect these faculties. 

  

Scientists said theirs is the first evidence to suggest structural brain changes and cognitive effects of just one or two uses of cannabis in young teenagers.

And it suggests as teenagers brains are still developing, they may be particularly vulnerable to the effects of THC.

In today’s cultural climate we all seem to recognize that something is wrong with the adolescent brain. We tend, as a rule, to blame it on social media and hand-held gadgets. And yet, if a third of 10^th graders have tried weed, we should also pay some attention to its influence on the developing brain. And we ought perhaps to be more judicious  before pronouncing it perfectly safe. And before encouraging its use:

Dr Orr concluded: 'Almost 35 per cent of American 10th graders have reported using cannabis and existing research suggests that initiation of cannabis use in adolescence is associated with long-term neurocognitive effects.

'We understand very little about the earliest effects of cannabis use, however, as most research is conducted in adults with a heavy pattern of lifetime use.

'This study presents evidence suggesting structural brain and cognitive effects of just one or two instances of cannabis use in adolescence.'