The study is parter of a larger study about marijuana and mood.
A new study from McLean Hospital found that people who begin smoking marijuana before the 16 have a harder time carrying out executive brain function than those who began smoking later in life.
The study, which is part of a larger study about the relationship between marijuana and mood, also found that those who began smoking before 16 smoke twice as often and three times as much marijuana than chronic smokers who started smoker later.
Staci Gruber, the director of the Cognitive and Clinical Neuroimaging Core at McLean Hospital and author of the study, said that she wasn’t surprised by the results.
“It’s a really compelling message that early exposure to marijuana results in not only high frequency and higher magnitude of use—at least in this small sample—it also results in a significant impairment in the ability to complete these tasks of frontal lobe function.”
The study found that chronic marijuana smokers had difficulty monitoring and changing behavior in social situations, reacting to social cues and inhibiting inappropriate behavior.
Researchers tested this using the Wisconsin Card Sort, where participants are given a deck of cards to sort and must change their sorting methods based on cues from the researchers, according to Gruber.
“Early onset smokers, ones that began chronic use prior to the age of 16, did significantly worse on these tasks than those who began smoking after the age of 16.”
The study was presented on November 16 at the Society for Neuroscience in San Diego.