Scientists at Indiana University have discovered that cannabidiol, or CBD, can offer protection against the long-term negative psychiatric effects of THC, the primary psychoactive ingredient in cannabis. Research has previously indicated that in some vulnerable populations, long-term use of cannabis increases adolescent drug users’ risk for certain neurological disorders, such as schizophrenia.
"This study confirms in an animal model that high-THC cannabis use by adolescents may have long-lasting behavioral effects," said lead author Dr. Ken Mackie, professor in the IU College of Arts and Sciences' Department of Psychological and Brain Sciences and director of the Linda and Jack Gill Center for Biomolecular Science at Indiana University. "It also suggests that strains of cannabis with similar levels of CBD and THC would pose significantly less long-term risk due to CBD's protective effect against THC."
THC, or tetrahydrocannabinol, is the chemical responsible for the “high” feeling and usually exhibits an indirect relationship with CBD. As selective breeding continues for higher and higher THC strains, it has been noted by the U.S. Drug Enforcement Administration that while THC levels rose 300 percent from 1995 to 2014, the levels of CBD have declined 60 percent. CBD produces no psychoactive effect and is an important ingredient in medical cannabis.
"This is the first study in a rigorously controlled animal model to find that CBD appears to protect the brain against the negative effects of chronic THC," Mackie said. "This is especially important since heavy use of cannabis with higher levels of THC poses a serious risk to adolescents."