Teenagers and young adults who use marijuana heavily grow up to develop brain abnormalities, but also a poor memory, a new study shows.
The research cannot say if the brain structure differences or the marijuana use came first, but it suggests that heavy marijuana use could have long-term effects. The study, conducted by a team from Northwestern University examined 97 volunteers with and without mental illness. The pot smokers said they had used marijuana daily since age 16 or 17, adding they had not used other drugs.
The results, published in the journal Hippocampus, showed that the daily marijuana users had an abnormally shaped hippocampus. They also performed approximately 18 percent more poorly on long-term memory tasks. The hippocampus is a part of the brain wich stores long-term memory.
Dr. John Csernansky, who worked on the study, said: “The memory processes that appear to be affected by cannabis are ones that we use every day to solve common problems and to sustain our relationships with friends and family.”
According to previous research carried out by the same team, heavy marijuana smokers and shown poor short-term and working memory, while the thalamus striatum and globus pallidus also had abnormal shapes in the brain structure.
The researchers said that the differences in hippocampus shape suggest that marijuana is the cause for the abnormal brain structures, even if a pre-existing vulnerability to pot abuse may also provide an explanation.
The scientists added that even after the volunteers stopped using marijuana, the effects lasted for another few years, into their early 20s. Also, the team found that people that suffer from schizophrenia who smoked pot did about 26 percent more poorly on memory tests than other schizophrenia patients.
In recent years, four states and the District of Columbia have legalized marijuana for recreational use. Twenty three states and Washington D.C. have legalized cannabis for medical purposes. Only this week, a group of U.S. senators pushed forward a bill that would prevent the federal government from prosecuting medical marijuana use in states where it is legal.
According to studies, marijuana is one of the safest substance to abuse. There are far less chances to die from marijuana abuse than from tobacco, alcohol or drugs like heroin. Cannabis have been found to help some medical conditions, such as nausea or cancer pain.
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