CBD, short for cannabidiol.
Now not only do we know that CBD works as an antipsychotic, we know
it targets the areas of the brain that need to be targeted. This really
gives us confidence, and it gives us scientific justification for large
scale clinical trials," lead researcher on the study Sagnik Bhattacharyya tells Inverse .
Scientists
compared brain scan results of people with a diagnosis of psychosis and
people without the disorder as they were doing a memory exercise. In
the people with psychosis, the researchers found clear differences in
the activity patterns in their prefrontal, mediotemporal, and striatal
areas of the brain — those that regulate decision making, learning and
memory. But when these participants were given a single dose of CBD,
their brain activity patterns were more similar to those of people
without the disorder. The results provide insight into which part
of the brain is affected by CBD and suggest CBD may curb symptoms of
psychosis in the human brain. The study was published Wednesday in Psychological Medicine
CBD and brain activity
The study included a group of 13
people with a diagnosis of psychosis and 16 people without the disorder.
The participants were asked to perform three different
verbal-association memory tasks (such as deciding whether words were
paired in a logical way, and recalling which words they’d previously
seen paired, or what font they were in) while in an fMRI machine. Those
with psychosis were already on standard antipsychotic treatment at the
start of the study, and they continued on the treatment throughout the
study. After taking scans of their brains to establish baseline
activity, the researchers then gave each participant a placebo drug and
then 600 mg of CBD, and rescanned their brains. The single dose of
CBD appeared to diminish the differences in activity in the brains with
psychosis and those without. For example, during memory exercises like
recalling something verbally, a brain affected by psychosis has abnormal
activity such as greater connectivity in the front of the brain
(prefrontal, mediotemporal and striatal areas), which makes it harder to
recall things logically. But after taking even just a single dose of
CBD activation in these areas tended to look similar to that of a person
without the condition. The results build on a 2018 study
from the same team suggesting that CBD can normalize brain activity in
people with symptoms of psychosis. This new study takes the work forward
by including people with a clear diagnosis.
Can CBD treat psychosis?
These results add to a growing body of research into the ways CBD may offer a treatment for different psychiatric conditions .
The need is great: Current gold-standard treatments tend to work only
in a subset of people and can have serious side effects when taken over
the long term. CBD may be easier for the body to process, making it a
more tolerable long-term option for people with chronic mental health
conditions, Bhattacharyya says. “This study is essentially showing
how CBD might work, and which effects might underlie symptoms of
psychosis,” he says. “But we seldom treat psychosis giving single doses;
we have to give doses for various weeks before seeing clinical,
meaningful results.” Ultimately, the study sample is too small to
draw definite conclusions on CBD as a treatment for psychosis patients
as a group. The study also doesn't look at how brain activity changes
matched up to behavior in the participants with psychosis — which means
we can't know if CBD improved their performance on the memory tasks. Bhattacharyya says his team is looking into further research on CBD
treatment for psychosis with larger samples and longer time frames. The
team also hopes to explore CBD as a potential treatment in other
disorders with similar symptoms, like Parkinson's or dementia. Abstract: Recent
evidence suggests that cannabidiol (CBD), a non-intoxicating ingredient
present in cannabis extract, has an antipsychotic effect in people with
established psychosis. However, the effect of CBD on the neurocognitive
mechanisms underlying psychosis is unknown. Patients with established
psychosis on standard antipsychotic treatment were studied on separate
days at least one week apart, to investigate the effects of a single
dose of orally administered CBD (600 mg) compared to a matched placebo
(PLB), using a double-blind, randomized, PLB-controlled,
repeated-measures, within-subject cross-over design. Three hours after
taking the study drug participants were scanned using a block design
functional magnetic resonance imaging (fMRI) paradigm, while performing a
verbal paired associate learning task. Fifteen psychosis patients
completed both study days, 13 completed both scanning sessions. Nineteen
healthy controls (HC) were also scanned using the same fMRI paradigm
under identical conditions, but without any drug administration. Effects
of CBD on brain activation measured using the blood oxygen
level-dependent hemodynamic response fMRI signal were studied in the
mediotemporal, prefrontal, and striatal regions of interest. Compared to
HC, psychosis patients under PLB had altered prefrontal activation
during verbal encoding, as well as altered mediotemporal and prefrontal
activation and greater mediotemporal-striatal functional connectivity
during verbal recall. CBD attenuated dysfunction in these regions such
that activation under its influence was intermediate between the PLB
condition and HC. CBD also attenuated hippocampal-striatal functional
connectivity and caused trend-level symptom reduction in psychosis
patients. This suggests that normalization of mediotemporal and
prefrontal dysfunction and mediotemporal-striatal functional
connectivity may underlie the antipsychotic effects of CBD.