Marijuana's effect on the brain: Your Say

Letter to the editor:

A recent study on differences in brain structures and marijuana use is getting a lot of attention for all the wrong reasons ("Casual marijuana use linked to brain changes").

Coverage of the story has heralded that casual marijuana use can cause brain abnormalities, which is very misleading. The researchers looked at brain differences between casual marijuana users and non-users at one point in time and saw a correlation. That is, the users' brains were different from non-users'. This kind of research says nothing about what caused the differences.

To do that, you need to look for brain changes following drug use over time, and even then it may be that these abnormalities incline individuals to smoke, or that someone inclined to smoke is also inclined to do other things that cause changes.

It's up to researchers to be very clear about what they did or did not prove. In this case, deliberately or not, the limits of their conclusions were lost in a cloud of smoke.

Alisa A. Padon; Baltimore

Comments from Facebook are edited for clarity and grammar:

Humans have used mind-altering substances throughout history. Nothing is going to stop it. It's up to individuals to decide for themselves what they will do and live with the consequences.

— Brett Vredenburg

That a study found pot use changes brain structure shouldn't surprise anyone. But it certainly will annoy all the people determined to get the drug and those who are trying to convince everyone that it's a harmless, miracle plant.

— Dave Melges

Why should people care about this result? Many people who take drugs want to change the way their brain is working.

— Eric Stapf