BLOOMINGTON – An Indiana University study using mice suggests that adolescent humans could suffer from marijuana with high levels of THC while being calmed by the presence of CBD in pot.
THC (tetrahydrocannabinol) gives the "high" to marijuana; CBD (cannabidiol) can counteract the "stoned" feeling.
"We found a variety of adverse effects of THC when given (to mice) during the adolescent period that we didn't see when given as adults, suggesting that you have this sort of vulnerable period during adolescence," said the lead author of the study, Ken Mackie, professor at the IU College of Arts and Sciences' Department of Psychological and Brain Sciences.
CBD appears to protect against the long-term negative affects of THC, the study found. The THC-associated psychiatric and neurological risks, such as schizophrenia, are greater among teens than among adults.
"One interpretation of our study is that it's not good for kids to smoke cannabis, but if they are going to smoke cannabis perhaps they should be smoking cannabis that has high CBD," Mackie said.
The IU study is relevant, Mackie said, as states move to legalize recreational marijuana and, as in Indiana, allow the use of CBD oil to diminish the pain of epileptic seizures.
For states where marijuana sales are legal, the study could suggest that labels be used to indicate the percentage of THC and CBD.
In his IU office Friday, Hatfield discussed the study on the same day that Indiana Gov. Eric J. Holcomb extended the time that state excise police can study CBD oil products. Holcomb also extended the moratorium on issuing citations or removing CBD oil products from retailers.
"Lawmakers have indicated they would like more time to consider proposed legislation," Holcomb said Friday in a statement. "For that reason, I am extending the education period for CBD oil products and the moratorium on issuing citations or removing products from retailers until the legislative session concludes."
Legislative bills have been introduced this session, which will end no later than March 14, to legalize medical marijuana in a state-monitored program, to legalize CBD oil and to create a summer study committee on medical marijuana's impact in other states.
Studies have shown that the market demand for high-potency cannabis has seen the THC content of seized cannabis in the U.S. increase from about 4 percent to 12 percent, according to the IU study. In turn, CBD content has decreased.
In 2016 about 13 percent of eight-graders said they had used cannabis.
Those statistics led IU researchers to study CBD.
As part of the study, mice were observed building nests by shredding paper towels in a repetitive behavior measured by researchers. After injections of THC, the mice shredded the paper in a compulsive manner, Mackie said.
"It's like hand washing. If you do it over and over and over again, you've done it excessively," explained Mackie.
In another test, injections of CBD seemed to suppress mice's anxiety.