JUN 04, 2019 1:00 PM PDT

Growing up high: new insights into how cannabis changes the adolescent brain

WRITTEN BY: Nina Lichtenberg

During adolescence, important cognitive functions develop. Adolescence is a highly sensitive period for brain development as it represents a time when regions of the frontal cortex in charge of higher-order cognition and regions deep in the brain responsible for emotional processing form connections with one another. Drug use, including cannabis, during adolescence can disrupt this circuit remodeling process.

On May 25th at the Canadian Neuroscience Meeting in Toronto, a group of neuroscientists presented the most recent findings on the effects of cannabis on the adolescent brain. Dr. Patricia Conrod, at Universite de Montreal, studied year-to-year changes in alcohol and cannabis use in a sample of students in the Greater Montreal region (a total of 3,826 7th grade students). Students were assessed for alcohol and cannabis use and given tests of their cognitive abilities annually for 4 years. Researchers found that substance use was linked to low cognitive functioning and that cannabis use, in particular, was associated with impairments in working memory, memory recall, and measures of self-control. This means that cannabis could have long-term effects on cognition, and that these effects are more pronounced than those resulting from alcohol use.

But how exactly does cannabis use change the brain and behavior? Dr. Steven Laviolette presented research on the effect of the primary psychoactive chemical in cannabis, delta-9-tetrahydrocannabidiol (or THC), on the adolescent brain, in rodents. Laviolette and his team found that THC in adolescence changes the prefrontal cortex (PFC), and in a circuit called the mesolimbic pathway, in a way that is similar to brain abnormalities observed in humans with schizophrenia. Importantly, this does not mean that cannabis use in adolescence leads to schizophrenia. But in addition to brain changes, researchers also revealed problems with social interactions, memory, and anxiety. These behavioral deficiencies could be reversed in early adulthood by administering drugs to restore normal PFC function.

In order to better understand the long-term effects of adolescent cannabis use on the brain, Dr. Jibran Khokhar, a neuroscientist at the University of Guelph, exposed adolescent rats to THC and then studied behavior in adulthood. The THC rats showed decreased lever pressing for rewards, which is thought of as characteristic of an "amotivation syndrome". Rats also showed an increase in Pavlovian or cue-reward learning (as measured by sign-tracking, or behavioral responding to reward-predictive cues). Brain connections were also altered in these animals. These results suggest that early THC exposure can produce long-lasting effects on behavior and brain circuits, even all the way into adulthood.

Taken together, these data expose possible ways to prevent and treat the long-term effects of adolescent cannabis use.

Source: EurekAlert!

About the Author
You May Also Like
OCT 04, 2019
Health & Medicine
OCT 04, 2019
Could Black Market Vape Pens Be Fatal?
Vaping products are becoming increasingly popular, both the legal and knock-off options. These products are currently driving what the medical community is...
OCT 04, 2019
Cannabis Sciences
OCT 04, 2019
THC Found in Almost Half of Popular Hemp-CBD Products
Many cannabidiol (CBD) products are assumed or advertised to be free, or mostly free, of Tetrahydrocannabinol (THC). A new study finds this is not always t...
NOV 15, 2019
Health & Medicine
NOV 15, 2019
Rise of Cannabis Use Disorder Due to Legalization?
The topic of cannabis use disorder is growing as marijuana becomes more commonly and openly used by the general public. In the past, research has been conf...
JAN 21, 2020
Cannabis Sciences
JAN 21, 2020
Smoking Weed May Cause Heart Problems, Study Finds
Researchers have found that there may be a link between smoking marijuana and cardiovascular problems including stroke and arrhythmia. Although cigarette s...
JAN 24, 2020
Cannabis Sciences
JAN 24, 2020
Sting Operation: Underage Customers Can't Buy Cannabis
Cannabis retailers in Colorado, Washington and Oregon have received top marks in secret tests to determine whether they were selling to underage buyers (yo...
FEB 23, 2020
Cannabis Sciences
FEB 23, 2020
Which is Better for you: CBD or THC?
Following the legalization of cannabis use, products derived from the plant are becoming more and more popular- especially those containing cannabidiol (CB...
Loading Comments...