Teens Who Use Marijuana Hurt Memory, Study Finds

Marijuana has been all over the news, with two states legalizing its recreational use and more than 20 legalizing the drug for medical use. Critics of these measures have voiced concerns that the increasingly casual attitude toward marijuana will harm people, especially young adults and teens. In many ways, marijuana is less harmful than other drugs, but it still carries risks. Now, research is pointing to some scary ways in which it could be harming teens.

Marijuana and the Teen Brain

The new evidence that smoking pot harms teenagers comes from research conducted at Northwestern University. The study included 97 young adults. Among the group were those who had never used marijuana and those who had, as well as those with schizophrenia, some of whom had used marijuana and some who had not. The young adults who had smoked pot did so when they were between the ages of 16 and 17. All the participants were subjected to MRI scans to image their brains and so the researchers could make comparisons between the four groups.

All of the participants who had smoked pot in the past, including those with schizophrenia and those without, had abnormalities in the area of their brains related to memory. This area was shrunken in size when compared to those that had never used marijuana. The impact of that shrinkage was demonstrated in memory tests. The participants that had never used marijuana scored significantly higher than those who did.

Marijuana and Schizophrenia

The researchers also made a connection between the effects of smoking pot on the brain and schizophrenia. While the participants who never smoked pot and did not have schizophrenia scored 37 times higher on memory tests, those who did have the disorder, yet never used marijuana, scored only four times higher. This indicates that memory problems caused by smoking pot may be similar to memory issues experienced as a result of having schizophrenia.

The researchers also discovered that among the participants that both had schizophrenia and had smoked pot, most of them began smoking before the disorder developed. This finding, along with earlier research, may suggest that marijuana contributes to the development of schizophrenia in young people.

In fact, earlier research has demonstrated a link between smoking marijuana and a risk for developing schizophrenia. A study from 2011 followed 2,000 teens who smoked pot as they grew into adults. Over 10 years, the teens who had smoked pot were five times more likely to develop schizophrenia.

Yet another 2011 study found that teens smoking marijuana increased their risk of having episodes of psychosis. Psychosis refers to unusual thought patterns or perceptions of the world that may include delusions, paranoia or hallucinations. Schizophrenia is one possible cause of psychosis. Among these teens, those most at risk were those who had a family member with schizophrenia or episodes of psychosis. They were already at risk themselves because of heredity, but smoking pot doubled the risk.

Although the research is mounting evidence that there is a connection between marijuana and schizophrenia, there is no clear proof yet that one causes the other. It could be that young people who will develop schizophrenia are more drawn to smoking pot as a way of self-medicating. More research needs to be done in order to pinpoint what is really happening. Even without conclusively proving that marijuana use contributes to schizophrenia, it is very clear that it impacts memory. Young people and their parents need to be aware of this risk.

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