Brain matures till age 26

I have read two articles in the last 10 days which seem to be very relevant to each other, although the authors did not note the connection.

The first was a review article (click here) stating that the human brain does not completely mature until about the age of 26 years, and that the particular circuits involved in that late maturing are based on cannabinoid receptors. “Recent studies show that cannabinoids manufactured by our own nerve cells play a crucial role in wiring the brain, both prenatally and during adolescence.”

Hence the not unreasonable assumption that teenage smokers of cannabis would likely interfere with that maturing.

The second research article (click here) talked about the corticostriatal network in the brain, which continues to develop until “at least age 25”. It went on to describe how that network connected areas involved in ‘reward’, to areas controlling behaviour. Their experiments showed that older subjects would modify their behaviour to perform better if the stakes were high, whereas adolescent subjects put the same amount of effort in, regardless of whether the stakes were high or low. This tends to explain why adolescents can be nonchalant about risky behaviour – statistically we know that adolescents drive more dangerously for example. They pointed out that evolutionarily speaking, this may not be bad – adolescents may spread their attention to a wide range of activities, before specialising more as adults. But, in modern life this may not work so well.

So, putting the two articles together, it maybe implies that adolescent cannabis smokers may prejudice their ability to mature in matching risk to reward.

I also wonder whether there is a case for raising the voting age to 25 or 26?