Marijuana Use Linked to Poor Memory

Heavy and prolonged use of marijuana changes the way the brain functions and even leads to poor memory, a new study has found.

The study was conducted by researchers at Northwestern Medicine® and was based on data obtained from teens and young adults.

Researchers found that chronic use of marijuana led to poor growth of brain region associated with memories. Also, marijuana-users had differences in brain structures resembling those seen in schizophrenia patients.

The study had 67 participants including controls. The test subjects in the study had begun drug use when they were about 16-17 years old. At the time of the current research, the test volunteers were marijuana free for about 2 years.

Researchers used MRI to assess the changes in deep subcortical gray matter of chronic marijuana users and compared the results with healthy people and schizophrenia patients. The study showed that marijuana is linked with poor working memory ability.

Working memory is the ability to store a piece of information for short-term use and if needed, send it for long-term storage ( people good at math have a good working memory).

"The study links the chronic use of marijuana to these concerning brain abnormalities that appear to last for at least a few years after people stop using it," said lead study author Matthew Smith, an assistant research professor in psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine, according to a news release. "With the movement to decriminalize marijuana, we need more research to understand its effect on the brain."

The study article is published in the journal Schizophrenia Bulletin.

Marijuana is a highly popular and an easily accessible drug. About 48 percent of all people in the United States have used the drug. Recent estimates from Centers for Disease Control and Prevention reported that more teens are smoking marijuana than cigarettes. Related studies have shown that they believe marijuana use to be less risky than smoking tobacco.