A recent study by Northwestern University researchers reveals that regular use of marijuana leads to abnormal changes in certain brain parts responsible for reasoning and memory and also increases the chances of schizophrenia.
"This paper is among the first to reveal that the use of marijuana may contribute to the changes in brain structure that have been associated with having schizophrenia," said John Csernansky, one of the senior researchers and co- author of the study in a statement.
The findings are based on MRI scans conducted on four groups of participants, reports NBC news. The first group with 44 volunteers was the controller group (the non-abusers), the second group comprised of 10 participants having cannabis disorder, the 15 participants in the third group were reported with both cannabis disorder and schizophrenia and the last group represented schizophrenic patients but with no reported marijuana usage.
All the participants were teenagers, the age group most vulnerable to marijuana usage, aged between 16 and 20. Three brain parts namely the striatum, thalamus and global pallidus of the volunteers were studied under MRI. The adolescents with heavy usage of marijuana were found to have abnormal changes in the brain parts. For example, the heavy abusers had shrunken thalamus, depicting a possible depletion of neurons, according to medical express. Thalamus is primarily responsible for memory related functions of brain.
Heavy users also performed badly in memory tests compared to others in the group (non users and non-schizophrenic).
In 2012 marijuana usage fell to 9.5 percent from 12 percent in 2002, according to a recent report by Abuse and Mental Health Services Administration. Nevertheless, millions of teens are still associated with excessive usage of the drug and are likely to develop schizophrenia symptoms earlier, reveals the study.
This is a breakthrough study in understanding the long term effects of marijuana usage but researchers are still not clear about the cause and effect of the malady; in the sense, whether irregular brain development leads to high usage of marijuana or vice-versa.
"We can identify certain differences, mainly in impulse control, related to the onset of substance use," Donald Dougherty, a co-author of the study, said in a statement. "But the key thing is that we do not know what impact drug use has on normal development. It may be that differences at the beginning leads to drug use, then drug use also impacts normal development. We can't tease these things out."
