Heavy Marijuana Use May Damage Brain Structures

In the United States, peoples' opinions are changing regarding marijuana use, with more and more states adopting medical marijuana programs and two states who have started the process of recreational legalization. Despite relaxed views on the drug, researchers are still working to find out the effects of the drug on the brain. A new study suggests that heavy use during the teenage years may damage brain structures vital to memory and reasoning.

Researchers observed changes in the sub-cortical regions of the brain using MRI scans, those regions are home to the memory and reasoning circuits, NBC News reports. Teenagers who had experienced changes to the sub-cortical region of the brain performed worse on memory tests (after two years of non-use) than their peers who had not used marijuana.

“We see that adolescents are at a very vulnerable stage neurodevelopmentally,” said lead researcher Matthew Smith of the Northwestern University Feinberg School of Medicine in Chicago. “And if you throw stuff into the brain that’s not supposed to be there, there are long-term implications for their development.”

Study participants were:

• 10 people with a history of cannabis use disorder.
• 15 people with a history of cannabis use disorder and schizophrenia.
• 28 people with schizophrenia but no regular marijuana use in their past.
• 44 healthy people without a history of marijuana use.

“We saw poor performance in the marijuana groups…” Smith said. “And the younger somebody started using, the more abnormal they looked.”

The results appear in the journal Schizophrenia Bulletin.

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