According to a recent research study by the journal Schizophrenia Bulletin, pot may be poorly affecting the memory and reasoning capability of teens using the drug heavily.
“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. “With the movement to decriminalize marijuana, we need more research to understand its effect on the brain.”
Smith and fellow researchers studied the brains of individuals in their early twenties who were identified as heavy marijuana users that began using between 16 and 17 years of age. Heavy usage was defined as smoking daily for about three years.
It was discovered that the majority of the subjects displayed altered sub-cortical regions, which are structures that play a crucial role in memory and reasoning circuits. In fact, memory-related structures within their brains tended to shrink and collapse inward — this indicates a possible decrease in neurons.
What made the study even more significant was the fact that those subjects hadn’t smoked pot for more than two years, on average. Those that displayed such alterations didn’t perform as well on memory tests as those who were identified as non-users, implicating that long-term usage can have lasting effects.
“We see that adolescents are at a very vulnerable stage neurodevelopmentally,” said Smith. “If you throw stuff into the brain that’s not supposed to be there, there are long-term implications for their development.”
What was even more troubling to Smith was the identified brain abnormalities look very similar to those found in individuals with schizophrenia-related issues. This is concerning because it means that changes in brain structure can lead to irreversible changes in brain function.
The study saw researchers make use of MRIs to identify and correlate abnormalities. This, coupled with carefully designed memory tests, led to the university’s findings.
Ninety-seven subjects participated in the study including equally matched groups of non-users, heavy marijuana users (back in their teen years), and schizophrenia subjects.