Study finds CBD reduces impairment caused by THC

By Brandon Dunn

A study published in the Journal of Psychopharmacology found that strains of cannabis containing the same levels of THC, but higher amounts of CBD were shown to cause less disruption to the parts of the brain linked to addiction and psychosis.

The study, conducted by a team from the UCL, led by Dr. Matt Wall, examined the effects of two strains of cannabis and placebo using fMRI (functional magnetic resonance imaging) to gauge how different strains of cannabis impact brain function in 17 healthy volunteers (experienced with cannabis, but not regular users) underwent three drug treatments and scanning sessions.

Treatments were cannabis containing THC (Cann−CBD; 8 mg THC), cannabis containing THC with CBD (Cann+CBD; 8 mg THC + 10 mg CBD), and matched placebo cannabis.

Volunteers also reported a reduction in feelings of being high while using the strains with increased amounts of CBD.

“We have now found that CBD appears to buffer the user against some of the acute effects of THC on the brain,” said Dr. Wall

The UCL study used MRI scans to monitor activation of different parts of the brain after using two strains of cannabis; one with a lower level of CBD and the other containing a higher level.

Findings reflect that the low-CBD strain disrupted signals from neurons in the posterior cingulate, leading volunteers to reporting an increased sense of feeling, “high or stoned,” as well as showing interference in the salience networks, which recognize and divert attention toward stimuli playing play an integral role in communication, social behavior, and self-awareness through the integration of sensory, emotional, and cognitive information.


This relationship between the posterior cingulate and subjective effects was also blocked by CBD.

Leading researchers to determine that higher CBD concentrations can restore disruptions to the salience network caused by THC exposure.

“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.

Researchers say their findings add to evidence that cannabis strains with greater CBD content may be less harmful.

“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.”

Dr. Matt Wall