In 2012, a study was published that followed over 1000 individuals for over 30 years to look at the impact of persistent cannabis use on the brain.
Based on IQ tests, blood samples and interviews with parents and teachers, here is what the researchers found:
- Those participants who used pot regularly before age 18 saw significant drops in IQ from childhood.
- Those who become regular pot user after the age of 21 did not get the IQ drop at all.
The scariest part? IQ’s in the kids who stopped regular use never recovered. The brain damage was permanent.
This piece of research created a lot of buzz, but a lot of controversy, too. Was the IQ loss really because of pot, or some other socio-economic factor? Many scientists weighed in calling the results of the study into question.
A follow-up study looking at twins and cannabis use showed that there was no evidence of cognitive decline in teens. However, the data was collected only by questionnaire and the questions lumped kids who only tried pot once in with those who smoked daily.
So which piece of research do you believe?
When research disagrees, I find a good starting point are these two questions:
- If the research isn’t clear, what’s the smart bet?
- Are we asking the right question?
1. The Smart Bet: Teen Brains Are a Work-in-Progress
As any parent of a teen can likely describe, the brains of teenagers are actively developing. This is particularly true in the frontal cortex, an area of the brain involved in memory, executive function and impulse control. Brain scans have shown that this is actively changing in the teen years and doesn’t fully mature into the early twenties.
Using any chemical on a daily basis during this period that might disrupt that seems like an idea that is really not worth banking on while we wait for scientists to figure out who has the best research.
There is no value in a normal, healthy teenager using pot regularly. So incurring the risks of using it, even if not fully proven, seems like bad bet. There’s no strong upside to regular teen use that I can see, so why argue about the science?
2. A Better Question: Why All the Pot?
Harmful or not, however, telling kids, “It’s bad for you,” doesn’t have a great track record for changing teen behaviour.
As is so often the case in medicine, sometimes it’s asking the right question that leads to a solution.
Instead of asking “Is regular pot use bad?”–which doesn’t work great for modifying teen behaviour–why not ask, “Why is my kid smoking so much pot?”
There’s no question that cannabis creates a state change. But what’s going on for teens who feel they need that state change every day?
While that alone won’t change behaviour, it might be a step toward something that can.