Western University researchers might have found a way to reverse the harmful effects marijuana can have on teenagers' brains.
Specifically, a recent study used pharmaceuticals to combat the negative psychiatric effects of THC, the psychoactive chemical found in marijuana.
Long-term adolescent marijuana use has previously been linked to the development of psychiatric diseases later in adulthood, like schizophrenia. Justine Renard, post-doctoral fellow and one of the study's team leads, also pointed to other negative effects like cognitive deficits, anxiety, lack of motivation and depression-like symptoms.
Researchers weren't sure what the link was between marijuana and psychiatric disorders until now. However, the study identified a specific mechanism.
Using adolescent rats, the researchers found that THC exposure regulates the activity of a neurotransmitter called GABA in the brain's prefrontal cortex region. The team looked at GABA because of its clinical association with schizophrenia.
The study found that adolescent THC exposure resulted in a reduction of GABA, causing the neurons in adulthood to be out of sync with each other. The loss of GABA in the cortex also led to a hyperactive state in the brain's dopamine system — as commonly observed with schizophrenia.
Finally, the team was able to reverse THC's adverse psychiatric effects by using drugs to activate GABA in a rat model of schizophrenia and eliminating symptoms.
Renard said adolescents' brains are particularly vulnerable to THC's harmful effects because the brain is maturing.
"There’s a lot of things taking place," she said. "The neurotransmitters are changing. If you use cannabis, the THC is going to act on specific receptors and mess up organization."
Going forward, the research team will look at how combinations of cannabinoid chemicals and GABA-boosting compounds could create more effective treatments for mental health disorders like depression and anxiety.
"Our findings help us to … find out what’s going on in the brain and why it’s important to keep marijuana out of adolescents' hands," said Renard.