August 11, 2014
Regular Marijuana Use Found To Have A Negative Impact On Teen Brains
redOrbit Staff & Wire Reports - Your Universe Online
Psychologists investigating the public health consequences of marijuana legalization have found a link between frequent cannabis use and cognitive decline, inattentiveness, memory decay and decreased IQ in teenagers.
According to Dr. Krista Lisdahl, director of the brain imaging and neuropsychology lab at University of Wisconsin-Milwaukee, those scans revealed abnormalities in gray matter (the part of the brain associated with intelligence) in 16- to 19-year-old teenagers who had increased their cannabis use over the past year.
Those results remained even after researchers controlled for variables such as serious medical conditions, prenatal exposure to drugs and learning disabilities, she added. That could be problematic, given that recent research indicates that marijuana use among high school seniors had climbed from 2.4 percent in 1993 to 6.5 percent in 2012, that 31 percent of young adults between the ages of 18 and 25 reported using the drug in the last month.
“It needs to be emphasized that regular cannabis use, which we consider once a week, is not safe and may result in addiction and neurocognitive damage, especially in youth,” Dr. Lisdahl said in a statement Saturday. “When considering legalization, policymakers need to address ways to prevent easy access to marijuana and provide additional treatment funding for adolescent and young adult users.”
Citing a 2012 longitudinal study that followed over 1,000 participants from birth to age 38, Dr. Lisdahl noted that men and women who become addicted to marijuana can lose an average of six IQ points by adulthood.
Her presentation, “Neurocognitive Consequences of Chronic Marijuana Use: Preventing Early Onset Is Critical,” was one of three at the conference’s “Considering Cannabis? Potential Public Health Implications of Marijuana Legalization” symposium, held Saturday at the Walter E. Washington Convention Center in Washington DC.
Also at the conference, Dr. Alan Budney of Darthmouth College warned that some legalized forms of marijuana contained higher research levels of THC – the substance responsible for most of its psychological effects. In his presentation, entitled "Clinical Epidemiology, Characteristics, Services and Outcomes for Youth With Cannabis-Use Disorders,” he explained that THC can increase the risk of depression, anxiety and psychosis in regular pot users.
“Recent studies suggest that this relationship between marijuana and mental illness may be moderated by how often marijuana is used and potency of the substance,” he explained. “Unfortunately, much of what we know from earlier research is based on smoking marijuana with much lower doses of THC than are commonly used today.”
People’s willingness to accept legalized medical marijuana has also had an impact on how risky adolescents perceive the substance to be, Dr. Bettina Friese of the Pacific Institute for Research and Evaluation in California explained in her seminar, “Is Legalization of Medical Marijuana Related to Youths' Marijuana Beliefs and Behaviors?”
Dr. Friese presented results of a 2013 study of over 17,000 Montana teenagers that discovered marijuana use among teens was higher in counties where a greater percentage of people had voted to legalize the substance for medicinal purposes in 2004. Furthermore, teens living in those counties were less likely to view cannabis use as dangerous, suggesting that a more accepting attitude of medical marijuana could have an even stronger impact on teens than the actual number of medical marijuana licenses available, she added.
In February researchers reported that legalizing the use of marijuana resulted in a dramatic increase in the number of children requiring emergency medical attention for exposure to the drug. That study found that unintentional marijuana exposures to children under the age of 10 had increased 30.3 percent from 2005 to 2011 in states where its use had been legalized.
“Pediatricians, toxicologists and emergency physicians need to be willing to advocate for the safety of children to lawmakers as this burgeoning industry expands across the US,” said lead author Dr. George Sam Wang of the Rocky Mountain Poison and Drug Center in Colorado. “As more states decriminalize marijuana, lawmakers should consider requirements – such as child-resistant packaging, warning labels and public education – to reduce the likelihood of ingestion by young children.”
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