When a teenager smokes cannabis are they permanently damaging their brain and dulling their intellect for a lifetime?

The dangers of smoking cannabis, and the potential health benefits, have been a source of controversy for many years.

The latest study on the drug suggested heavy and prolonged cannabis smoking as a teenager resulted in a permanently lower IQ. You can read Dominic Hughes’s report on the findings here.

But how could cannabis have this effect on the brain and why might teenagers be particularly susceptible?

The drug is made from the cannabis plant and contains more than 400 different chemicals, which could have a range of effects on the mind and body.

It includes psychoactive chemicals, which act on the brain. The main element is a chemical called tetrahydrocannabinol (THC). This provides the “chilled out” sensation associated with smoking cannabis, but has also been linked to memory impairment.

Brain chemistry

Some of these chemicals are already in all our brains, cannabis smokers or not, as the brain has its own endocannabinoid system.

Prof Val Curran, from the British Association for Psychopharmacology and University College London, said: “Any drug will affect the brain’s natural chemistry.

“We believe cannabis use can affect the natural cannabinoid system.”

But how could persistent use have a heightened impact on the teenage brain? The study noticed a difference between drug use before and after the 18th birthday.

Read more here