The number of adolescents and young adults using marijuana on a regular basis is increasing,

and some states are legalizing recreational marijuana.

But regulating its use among young people is a challenge that needs to be considered in light of scientific research,

says neuropsychologist Krista Lizdahl.

In this episode, she talks about why chronic marijuana use is especially toxic to teenagers' brains,

even more so now than a few decades ago.

I'm Audrey Hamilton, and this is Speaking of Psychology.

Psychologist Krista Lizdahl is Director of the brain imaging and neuropsychology laboratory at the

University of Wisconsin, Milwaukee. Using magnetic resonance imaging or MRI, she studies the

neurocognitive consequences of chronic drug use on the brains of teenagers and young adults. Welcome,

Dr. Lizdahl. Thank you. It's a pleasure to be here. Years ago, there was a television public service announcement aimed at teenagers that showed an egg

frying in a pen. You remember that. And announcer saying, this is your brain on drugs.

Very dramatic. It was memorable to a lot of kids of that generation. Do you think people,

specifically teenagers, really understand what marijuana you specifically can do to their brains?

And is it increasing among teenagers?

So for the first question, do they understand what it really does to the brain?

I would have to say for the vast majority, no, there's not a good understanding.

In fact, a lot of people that I talk to, it seems like they don't even understand the concept that marijuana is a drug that gets in the brain, and that's where the effects come from. A lot of times the attitude is that, you know, marijuana is just an herb. Why would it affect you? It's safe as though it's something like mint, you know, it's,

that it's not a psychoactive drug. The other question is, is marijuana use increasing among

teens? We have seen an increase, actually, specifically in heavy regular use, which is most

alarming to me because that's when we see more than negative health effects.

So since we've had the highest rates since the 1980s, in the last five years or so, it's gone up from about 2% of high school seniors using daily all the way up to almost 7%.

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