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New study shows casual marijuana use causes brain abnormalities in the young

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As Minnesota lawmakers weigh whether to legalize medical marijuana, a new study shows smoking marijuana recreationally could lead to harmful changes in the brains of young people.

Experts say the findings are significant because young peoples’ brains are still developing.

The study in the Journal of Neuroscience perhaps confirms what has long been the cliché of spacey potheads.

It also offers a new detailed look into exactly how young brains are affected by smoking marijuana.

"This study raises a strong challenge to the idea that casual marijuana use isn't associated with bad consequences," co-senior study author Dr. Hans Beiter from Northwestern University says.

Science Daily reports researchers compared the size, shape, and density of the nucleus accumbens and the amygdala – a brain region that plays a central role in emotion – in 20 marijuana users and 20 non-users.

Researchers also found a direct correlation between the number of times users smoked and abnormalities in the brain. A brain region called the nucleus accumbens, known to be involved in reward processing -- was larger and altered in its shape and structure in the marijuana users compared to non-users.

"What we're seeing is changes in people who are 18 to 25 in core brain regions that you never, ever want to fool around with," co-senior study author Dr. Hans Beiter, professor of psychiatry and behavioral sciences at Northwestern University, told Reuters.

He says he has become convinced that marijuana should only be used by people under 30 if they need it to manage pain from a terminal illness.

Researchers say the findings also highlight the importance of research aimed at understanding the long-term effects of low to moderate marijuana use on the brain.

More than 18 million people report using marijuana, according to the most current analysis of the National Survey on Drug Use and Mental Health.

Previous research into how tetrahydrocannabinol (THC) – the main psychoactive component of marijuana – affected animal brains showed changes to regions associated with motivation, attention, learning and memory.

Less has been known until now about how low to moderate marijuana use affects brain structure in people, particularly in teens and young adults.

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