Marijuana use by teens with still-developing brains may drop their IQ by an average eight points according to a study conducted by Duke University researchers.
The study was conducted with 1,037 participants from Dunedin, New Zealand. The researchers tested the IQs of participants five times from the ages of 13 to 38. Researchers compared their IQ scores at the ages of 13 and 38, and found a drop in IQ those who had regularly smoked pot by the age of 18.
Marijuana users deemed dependant on the drug lost an average of eight IQ points. Dependent means continual use of the substance even as social and physiological statuses deteriorate.
“While eight IQ points may not sound like a lot on a scale where 100 is the mean, a loss from an IQ of 100 to 92 represents a drop from being in the 50th percentile to being in the 29th,” according to Madeline Meier, Duke University post-doctoral researcher. “Somebody who loses eight IQ points as an adolescent may be disadvantaged compared to their same-age peers for years to come.”
Earlier research has provided information that THC from marijuana has effects on the receptors of the brain causing short-term memory problems, poor motor skills, and a loss of coordination. This research coincides with interviews of family members of the Dunedin study.
“Marijuana impacts every individual in a different way,” said Chris Cubero, SRU counselor and assistant professor. “This is believed to be based on how many receptor sites are in the brain.”
According to the National Institute on Drug Abuse’s website, marijuana is the most commonly abused illicit drug in the United States.
A Partnership Attitude Tracking (PAT) study reports that heavy marijuana is up 80 percent since 2008. Heavy use was defined by smoking marijuana at least 20 times in the last 30 days.
The PAT study also showed that 51 percent of teenagers think regular marijuana use is a risky behavior. This is down from 61 percent from 2005 data.
This is the first study to look into brain functions before marijuana use. More studies will have to be performed to find conclusive evidence of long-term adverse effects on the brain from marijuana use.
With growing trends of teenagers having a positive attitude towards marijuana use, there is a need for new research. Marijuana doesn’t only affect the brain, but it can also affect lungs and sexual processes.
“What we do know is correct is, you’re burning a substance and smoke is entering your lungs and that’s where major damage can occur,” said Cubero.
“The new findings aren’t definitive, but they underscore the importance of studying how marijuana may harm young people,” Ken Winters, a psychiatry professor at the University of Minnesota and senior scientist at the Treatment Research Institute said.