CBD May Protect the Brain From THC’s Effects
Consuming cannabis with higher levels of CBD causes less brain disruption, according to a new study from University College London.
The researchers claim that the famously calming cannabinoid can protect against the harsher effects of THC.
“We have now found that CBD appears to buffer the user against some of the acute effects of THC on the brain,” said the study's lead author, Dr Matt Wall.
“Over the last two decades, rates of addiction and psychosis linked to cannabis have been on the rise, while at the same time stronger strains of cannabis with more THC and less CBD have become increasingly common,” he explained in a press statement.
The research, which was published in the Journal of Psychopharmacology, is the first study to use fMRI (functional magnetic resonance imaging) to gauge how different varieties of cannabis impact brain function.
The researchers monitored the brain activity of 17 participants at rest after they consumed one of two different strengths of cannabis.
The two varieties both has equal levels of THC but differed dramatically on CBD levels; one type contained high levels of CBD, while the other, a skunk product, contained negligible levels of the calming cannabinoid. The strains were chosen as they were reflective of common products within the UK’s illegal recreational market.
The researchers found that the cannabis with low levels of CBD impaired the participants’ brain functions. The drug degraded the brain’s salience network, a system of detecting emotional and sensory stimuli, and its general functional connectivity. Disruption to the brain’s salience network has previously been linked to addiction and psychosis.
However, the high-CBD variety only caused a minimal disruption to these brain regions, suggesting that the CBD counteracts some of THC's harmful effects.
The study also showed how THC can induce disruption in the brain’s posterior cingulate, a neural region associated awareness and episodic memory retrieval. These disruptions were strongly correlated with participants' reports of feeling more “stoned” or “high”, which suggests that the brain area may be central to producing cannabis' elating effects.
This relationship between the posterior cingulate and the “stoned” feelings was also blocked by CBD.
The researchers claim that their findings add to evidence that cannabis varieties with greater CBD content may be less harmful to consumers.
“As cannabis is becoming legal in more parts of the world, people buying cannabis should be able to make an informed decision about their choice of cannabis strain and be aware of the relative risks,” said Dr Wall.
But the study’s most salient result may be how it demonstrates CBD’s efficacy in certain medical treatments.
“If CBD can restore disruption to the salience network, this could be a neuroprotective mechanism to explain its potential to treat disorders of salience such as psychosis and addiction,” added senior author Professor Val Curran.