Long-Term Marijuana Use May Damage Short-Term Memory

Long-Term Marijuana Use May Damage Short-Term Memory

Long-Term Marijuana Use May Damage Short-Term Memory

Long-Term Marijuana Use May Damage Short-Term MemoryWith some states legalizing marijuana more studies on how marijuana affects those who use it chronically and casually are being launched. Previous studies have researched how marijuana use affects the brain’s cortex. A new study shows how chronic marijuana use may change the brain’s actual structure, damaging a person’s working, or short-term, memory.

A Change in Brain Structure

After years of using marijuana a group of teens had developed abnormal changes in the structure of their brains. Their working memory had decreased, and they could not successfully perform some memory tasks. These teens had smoked marijuana every day for nearly three years. When they were in their twenties, a group of researchers from Northwestern University studied how marijuana had actually changed the structure of their brains.

The structures in the brains of the twenty-something participants that were related to memory had shrunk and collapsed inwards. As they age that memory won’t improve. When the Northwestern Medicine study began, the participants had not smoked marijuana for the previous two years. Even after those two years, the memory problems were still there.

Most of the participants began smoking marijuana daily when they were between 16 and 17 years old. Researchers found that the younger the participant was when they started using marijuana, the greater the structural changes in the brain.

Losing Short-Term Memory

Losing your short-term memory in your twenties means that it will be worse in your eighties. It’s common for people to have worse working memory as they age. But if teen users impair their working memory, imagine how difficult it will be for them to remember directions, a phone number or a person’s name when they are older. The working memory helps people process information and moves that information to the long-term memory.

While other marijuana studies analyzed the cortex of the brain to see how marijuana affected rewards and motivation, the researchers from Northwestern studied a different part of the brain. According to Dr. Hans Breiter, the co-senior study author, this is the first marijuana study to use a structural MRI and analyze marijuana’s effects on the deep subcortical gray matter of the brain where working memory functions.

Marijuana’s Relationship with Schizophrenia

Previous studies on marijuana use had studied the relationship between marijuana and schizophrenia. Those studies suggested a link between abusing marijuana and developing schizophrenia. This new study reinforced those theories.

Of the 97 participants in the study, 15 were individuals who had schizophrenia and a marijuana addiction. There were also other individuals in the study who had schizophrenia but who had never had a substance abuse disorder. Researchers found that 90 percent of those 15 individuals developed schizophrenia after they had heavily used marijuana. The brain abnormalities induced by marijuana use also greatly resembled the same types of abnormalities found in individuals with schizophrenia.

The Northwestern study, according to Dr. Breiter, is one of the first to compare how the changes in the brain structure of someone who has chronically used marijuana is similar to the brain structural changes in individuals who have schizophrenia. This finding highlights a dangerous possible relationship between marijuana abuse and mental illness.

What if teens who are battling a mental illness or who are at risk for developing a mental illness start using marijuana? Dr. John Csernansky, the study’s other co-senior author, fears that mixing marijuana and mental illness may only cause the mental illness to further develop.

More longitudinal studies need to be conducted on this topic, but until then researchers hope that those who are battling a mental illness reach out to specialists who can help, rather than turning to marijuana or other street drugs that may only make things worse.

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