The Effect of Cannabidiol (CBD) on the Short-Term Memory of young Drosophila melanogaster Research that is focused on memory is prominent in modern times because age-related memory loss is a CBD is known for its antioxidative and neuroprotective effects. For these reasons, many people take CBD oil to improve memory. Where exactly does CBD excel at when it comes to our memory functioning? Learn more about CBD and its use for the brain. <span><b>Background:</b> Accumulating evidence suggests that the non-intoxicating cannabinoid compound cannabidiol (CBD) may have antipsychotic and anxiolytic properties, and thus may be a promising new agent in the treatment of psychotic and anxiety disorders. However, the neurobiological substrates unde</span> …
The Effect of Cannabidiol (CBD) on the Short-Term Memory of young Drosophila melanogaster
Research that is focused on memory is prominent in modern times because age-related memory loss is a growing issue throughout the world. Previous research has suggested that cannabidiol (CBD) can improve the memory of the elderly suffering from neurodegenerative diseases. However, the effect that CBD has on the memory of young people has not been extensively studied. Here we show that CBD does not improve the short-term memory of young male D. melanogaster. Our finding has contradicted the known knowledge of how CBD could potentially be used for memory loss. Our results suggest that exposure to CBD may result in impairment of the short-term memory and cause erratic behavior in young organisms. These outcomes could be a starting point for future study on the effect that CBD may have on young humans.
Memory plays a major role in adapting to a habitat and acquiring various skills. Learning is essential for memory, and memory allows organisms to recall the information they learned and use it whenever they need to. There are two main types of memories pertaining to humans: long-term and short-term memory (Cowan, 2008). Long-term memory is a remembrance of events that have taken place at an early time of one’s life and cannot be forgotten easily. Short-term memory is the remembrance of actions or events that have occurred recently and can be forgotten quickly (Cowan, 2008). There are important factors that can cause damage to short-term memory such as aging, physical injury, and substance abuse. Short-term memory impairment increases as humans age. Throughout the world, there is an estimate of 50 million people with dementia. This number is expected to grow by 10 million cases every year (World Health Organization, 2020).
Substance abuse has been a growing issue throughout the world. One of these substances is Cannabis, found in the Cannabis sativa plant, and is commonly known as Marijuana. Two major components found in Cannabis are Cannabidiol (CBD), which is not a mind-altering component and Tetrahydrocannabinol (THC), which is a mind-altering component (Schoeler and Bhattacharyya, 2013). CBD has several positive effects on the human body, such as reducing neuroinflammation, reducing brain damage caused by neurodegenerative diseases, promoting the production of new neurons in the brain, and raising levels of synaptic plasticity in the brain (Maroon and Bost, 2018). However, there are negative effects of CBD which include irritability, extreme tiredness, and nausea (Grinspoon, 2018). Previous studies have stated that CBD can improve the memory of people over the age of 65 with neurodegenerative diseases (McGuire et al., 2017). Currently, there is not a large amount of research on how CBD affects the memory of people under the age of 25 years old.
The current study aims to test if CBD improves the short-term memory of young male Drosophila melanogaster, commonly known as fruit flies. This organism is ideal for this study as it is easy to maintain, and it reproduces fairly quickly. Drosophila also have a short life span, which allows us to study short-term memory in a limited period of time. We hypothesized that exposure to CBD may improve the short-term memory of the male D. melanogaster when the aversive phototaxic suppression assay (APSA) is performed.
Materials & Methods
Fly stock and rearing conditions
A wildtype D. melanogaster Oregon R is used in this study. Flies were reared in tubes containing cornmeal media. They were flipped into fresh media every three weeks and were kept in a 20oC chamber. For this study, we used flies that were up to two weeks old.
Pilot Study: Testing the Amount of CBD To Use
Prior to performing the experiment, the amount of CBD oil (Fisher Scientific, 1 mg/mL CBD in 1 mL ethanol or methanol) that the flies were exposed to was determined by exposing the flies to fly food that contained differing amounts of CBD. The flies consumed food that contained 0.4 mL, 0.2 mL, 0.1 mL, 0.075 mL, or 0.050 mL of CBD. The CBD was mixed into the food along with 2 mL of water. Based on our data, we decided that 0.050 mL of CBD (0.025 M CBD solution) was appropriate for our experiment. The control was the same amount of ethanol without CBD.
Pilot Study: Testing the Experimental Apparatus
Figure 1. This apparatus used for the phototaxis test and APSA test. Quinine hydrochloride solution was applied on the inside of the lighted tube (left). It was used to test whether the fly was sighted or not, was used for the learning and short-term memory tests.
The efficiency of the experimental apparatus we made for the current study was tested (Fig.1). Tube 1 contained 1.8 g of fly food, 2 mL of 1MΩ water, and 0. 05 mL of CBD solution. Tube 2 contained 1.8 g of fly food, 2 mL of 1MΩ water, and 0.05 mL of 95% ethanol as the control. The fly food containing ethanol was used as our control because the CBD was dissolved in ethanol. The students transferred 3 young flies into each tube, so they were exposed to these food conditions for 24 hours, and then the Aversive Phototaxic Suppression Assay was performed on each fly for 6 trials.
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The phototaxis test examines an organism’s innate ability to move towards light (Nakamura and Yamashita, 1997). Each fly was transferred into a dark tube, which was covered in aluminum foil, and then the room was made dark. The fly was allowed to acclimate to the dark for 1 minute. Another tube was then connected to the dark tube, and a light was flashed from above on to the tube that was not covered in aluminum foil (lighted tube). The fly was given the option to move to the lighted tube or stay in the dark tube. The fly that was positively phototaxic moved towards the light (Nakamura and Yamashita, 1997) if they were sighted within 30 seconds. We performed the phototaxis test to eliminate the blind flies (or those with abnormal visual function) for the APSA.
Aversive Phototaxic Suppression Assay (APSA)
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This test trained the fly to remain in the dark side of the apparatus (Seugnet et al., 2009). Prior to the Aversive Phototaxic Suppression Assay (APSA), the flies were exposed to either diets (CBD-infused food or control food) for 24 hours. Then they were starved for 6 hours before starting the Aversive Phototaxic Suppression Assay. In this assay, two plastic tubes were used, one was covered in aluminum foil to create darkness and the other one was left uncovered. The uncovered tube was coated with a 1M solution of quinine hydrochloride, a bitter substance that repels the flies (Hayes et al., 2015). Each fly was transferred to the dark tube, the room was made dark, and the fly was allowed to acclimate to the dark for 1 minute. The uncovered tube containing quinine was then connected to the dark tube. A white light from a smartphone device was flashed on the uncovered tube and immediately a timer was started when the two tubes were connected. The timer was stopped once the fly touched the quinine on the lighted side of the tube. The students performed 10 trials and after each trial, the fly was tapped back into the dark tube and was allowed to rest for 30 seconds and re-acclimate to the darkness. After the learning test was performed, the flies were starved again for 6 hours so that their short-term memory could be tested. The memory test was just one trial. It is the same procedure as the learning test to determine if the flies remember what they had learned 6 hours ago.
First, we measured how many trials it took for the young male flies to learn. To do this, we performed the APSA (Materials and Methods). During the 10 trials, the flies exposed to the control food did not show a significant change until the 7th trial (Fig. 2b). There was a significant difference after the 8th trial. We interpreted this as the flies in the control group learned at the 8th trial. In the CBD treatment group, we found that the flies did not show a significant change throughout all 10 trials (Fig. 2c). We interpreted this as the flies in the CBD group did not learn at all.
We found that there was a wide variation of average avoidance times for each trial. (Fig. 2c) This could be the result of the CBD effect on the flies. We observed that some of the young male flies that were exposed to the CBD-infused food had very erratic behavior, which is described by abnormal movements of the flies, while others had sluggish or normal behavior. This could explain why the average avoidance times varied.
Second, we tested the effect of CBD on their short-term memory. To do this, the flies were starved for 6 hours and then the APSA was repeated once (Materials and Methods). We found that the flies exposed to the control food did not surpass the threshold avoidance time (Table 1). We interpreted this as the flies not remembering what they had learned. In the CBD treatment group, we could not calculate a threshold avoidance time because the flies did not learn throughout the 10 trials of the learning test. Therefore, since the flies did not learn, it is impossible for them to have remembered.
Table 1: Table shows the results of the memory test for flies exposed to control and CBD-infused food. The threshold avoidance time for the control group was 112.9 s. The threshold avoidance time was calculated by taking the average of the averaged trials that the flies learned in. (Threshold for control flies: average of the mean trials 8, 9, and 10). The flies whose avoidance times passed this threshold remembered what they learned. According to the learning test results, none of the control flies remembered what they learned. The flies exposed to CBD-infused food did not learn, so they do not have a threshold avoidance time. Since the flies did not learn, they did not remember.
This study focuses on the effect of CBD on young male D. melanogaster’s short-term memory. In order to do this, APSA was performed to observe whether a CBD-infused diet improved their learning or not. Using the APSA, 10 trials were conducted for the learning test, and then a 6-hour starvation gap was given before performing only one trial of the APSA again to test their memory. Figure 2 shows the results of the APSA tests for the control and CBD treated flies. We hypothesized that the CBD group would learn quicker than the control group. However, our results showed that the flies in the CBD group did not learn at all. Fig.1b shows a graph of the 10 trials of the learning test for the flies exposed to control food. The results of the Kruskal-Wallis test showed that trials 1-7 showed no significant learning in the flies (p>0.05), and trials 8-10 showed no significant learning in the flies (p>0.05). A Mann-Whitney test was done comparing trials 1-7 to trials 8-10 (p<0.05). This shows that the flies did not learn at the 8th trial as the control flies did. Also, since the results of the learning test in the CBD treated flies was erratic, we concluded that the flies did not learn at all during the 10 trials.
Fig.1c shows a graph of the 10 trials of the learning test for the flies exposed to CBD-infused food. The results of the Kruskal-Wallis test showed that trials 1-7 had no significant learning in the flies (p>0.05), and trials 8-10 showed no significant learning in the flies (p>0.05). A Mann-Whitney test was done comparing trials 1-7 to trials 8-10 (p>0.05). This shows that the flies did not learn at the 8th trial as the control flies did. Also, since the results of the learning test in the CBD treated flies was erratic, we concluded that the flies did not learn at all during the 10 trials.
Figure 2: Results of the Phototaxic Suppression Assay. a) Graph comparing the average avoidance times for each trial in the learning tests for male D. melanogaster in the control and CBD diets. b) Graph showing the 10 trials of the learning test for the flies exposed to control food (n=3). The p-values show that the flies learned at trial 8 (p<0.05). c) Graph showing the 10 trials of the learning test for the flies exposed to CBD-infused food (n=4). The p-values show that the flies did not learn at any trial.
Finally, we repeated one trial of the APSA 6 hours after the learning tests to determine if the flies remembered what they had learned. The threshold avoidance time for the flies exposed to the control food was 112.9 seconds (Table 1). Since none of the flies exposed to the control food surpassed the threshold avoidance time during the memory test, we conclude that none of them remembered what they had learned. A possible reason for this could be that the ethanol had a psychiatric effect on the flies that impaired their short-term memory. For the CBD group, it was impossible to calculate a threshold avoidance time because they did not learn. As a result, we cannot make conclusions about the CBD treated flies’ memory since they did not learn. However, it is interesting to note that fly 1 and fly 2 had a higher avoidance time compared to fly 3 and fly 4 (Table 1). Here, 2 groups can be seen, one group where there is high avoidance time and one group where the avoidance time is low. We assume there may be a psychiatric effect on each fly causing each one to behave differently compared to another fly. The CBD may not be 100% pure and may contain another major component of cannabis called tetrahydrocannabinol (THC) which has a mind-altering effect. This may be a reason why the flies behaved in a contrasting manner. Another factor could be that the flies may have had a genetic variation that was contributing to affecting each fly differently.
We conclude that CBD has an inhibitory effect on the short-term memory of male Drosophila melanogaster as they did not learn during the learning test nor did they remember during the memory test. We found that time was an essential component to perform this experiment. We were also researching other variables such as sex difference and age difference, but our sample size was too small due to the death of many flies.
The authors would like to thank Dr. Kwangwon Lee and Dr. Nathan Fried for their guidance and support, Sarah Johnson for ordering supplies, Taqdees Gohar for assisting with the experimental plan, and Harjit Khaira for providing fly supplies and advice.
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Seugnet, L., Suzuki, Y., Stidd, R., and Shaw, P.J. (2009). Aversive phototaxic suppression: evaluation of a short-term memory assay in Drosophila melanogaster. Genes Brain Behav. 8, 377–389.
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McGuire, P., Robson, P., Cubala, W.J., Vasile, D., Morrison, P.D., Barron, R., Taylor, A., and Wright, S. (2017). Cannabidiol (CBD) as an Adjunctive Therapy in Schizophrenia: A Multicenter Randomized Controlled Trial. AJP 175, 225–231.
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CBD and Memory: Can Hemp Oil Enhance Memory?
Cannabis users have long been thought of as people with short-term memory problems due to an alleged negative impact of cannabinoids — the active ingredients in cannabis plants — on the brain cells.
Ironically, the infamous THC has been recently shown to have neuroprotective effects on brain cells during studies. This means that cannabis, instead of killing healthy brain cells, protects them against damage. This fairly recent discovery sheds new light on the potential use of cannabinoids in the treatment of memory issues.
And as for CBD, neuroprotection is believed to be one of the compound’s major roles.
So, have we been misinformed all that time?
Apparently yes, but this isn’t the subject of our article.
Today, we’re going to cover CBD’s potential in fighting Cognitive Decline (CD), the scientific term used to diagnose memory loss. The condition is more likely to occur with aging; that’s why learning more about CBD, including its effects on catabolic processes in the brain, is essential to understand how it can help with memory issues.
Does CBD Help with Memory?
In recent years, CBD has been found to alleviate certain symptoms of memory loss conditions, including different types of dementia. People are turning to CBD oil to treat Alzheimer’s disease as well as to improve focus and enhance the daily performance of their brains.
We have all experienced temporary memory glitches, but if memory loss becomes chronic and compromises your daily functioning, it may be time to seek out treatment.
CBD interacts with the master regulatory network known as the endocannabinoid system (ECS). From there, it operates on over 65 molecular pathways, ensuring the balanced functioning of ECS and the maintenance of homeostasis (1). Homeostasis is a biological term describing the harmony between all biological functions in the human body.
The interaction between CBD and the central nervous system (CNS) is where the cannabinoid manifests its benefits for memory.
In the next section, we cover the most common memory issues CBD is known to help with, and back it up with scientific research.
CBD and Memory Issues: The Benefits
Perhaps the most important benefit of CBD for people with memory problems is that the compound is non-intoxicating. Unlike THC, CBD won’t get you high because it doesn’t have a direct affinity to any of the cannabinoid receptors in the brain. CBD can even negate the psychotropic potential of CBD by blocking the sites of these receptors when THC tries to bind to them.
THC can help enhance memory in people with neurodegenerative disorders, but as we said, this article focuses specifically on CBD. And if you’re reading this, you’re probably interested in achieving memory improvements without the psychoactive buzz.
CBD has been established as a potential remedy for people who struggle with a variety of cognitive disorders. However, because the research is in its early stages, more studies in this regard are needed to confirm preclinical findings.
For now, let’s focus on the most important studies investigating the efficacy of CBD for common memory ailments.
CBD for Alzheimer’s and Dementia Memory Loss
Memory loss triggered by degenerative conditions, such as dementia and Alzheimer’s disease, is a significant area that CBD oil has been shown to alleviate inflammation of the brain, reduce oxidative stress, and improve the regeneration of neurons, all of which can help improve cognitive performance.
Patients with Alzheimer’s disease experience progressive cognitive decline due to the degeneration of neurons in the brain, which further destroys neural pathways. Numerous studies have shown that CBD oil not only prevents the destruction of these neurons, but it also aids the body in creating new ones (neurogenesis). (2)
CBD for Memory Loss Caused by Stress and Anxiety
While analyzing the impact of CBD on the brain cells, researchers have discovered that it can actually mitigate brain damage caused by physical trauma and severe stress.
Studies have shown that the body starts to release endocannabinoids (the body’s version of plant-based cannabinoids) to defend the brain and repair it (3). When phytocannabinoids like CBD are administered to the endocannabinoid system, it strengthens the defensive response, therefore strengthening the memory.
Moreover, there is a large body of evidence supporting the use of CBD in the treatment of traumatic brain injury that derives from neuroinflammation (4). Since CBD is such a potent anti-inflammatory compound, it could help you after memory loss caused by an injury that brought inflammation to your brain.
CBD for Memory Loss Due to Lack of Focus
If your memory issues are caused by an inability to focus, CBD oil may come in handy, as shown by studies that tested the efficacy of CBD as a potential treatment for ADHD, including children.
In a review published in the Journal of Pediatric Pharmacology and Therapeutics, the authors reported that CBD oil had been shown to support people with a range of medical conditions, including the behavioral symptoms of ADHD, such as a short attention span (5). Another study mentions anxiolytic (anti-anxiety) and sleep-regulating properties of CBD, both of which contribute to better memory retention (6).
However, it is unclear whether CBD oil can improve your cognitive function if your memory loss doesn’t stem from a diagnosed condition or disease. A comprehensive review of 27 previously conducted studies found that apart from improving the mental health of patients with schizophrenia, CBD oil didn’t have significant effects on memory functioning in otherwise healthy subjects (7).
So, whether the therapeutic effects of CBD on the brain are universal is still up to debate; that’s why we need more longitudinal human trials to draw definitive conclusions on CBD as a memory booster.
CBD, Memory, and Addiction
In addition to the aforementioned publications, an additional study suggests that CBD may be a promising treatment for people recovering from addiction due to its effect on memory (8).
The study introduces the idea of CBD having “a disruptive effect on reconsolidation of contextual drug-related memories.” It also highlights CBD’s potential to “attenuate contextual memories” from drug abuse, reducing the risk of relapse.
In simple words, the study concludes that CBD can help with addiction by altering memories linked to substance use.
The research team used cue exposure to tempt mice with a rewarding drug (morphine) and observed that taking CBD disrupted the cue. In a perfect world, this would mean that human cravings in addicts can be curbed with CBD too.
Long story short, the effects of CBD on memory may help addicts unlearn the habits of addiction. These habits give rise to cravings and pose a risk of relapse, long after withdrawal symptoms are gone. Some research also suggests that since CBD affects the memory in such a fashion, it may be able to help addicts in recovery by dissociating experiences with substance abuse.
What Else Does the Research Say About Taking CBD for Memory Enhancement?
Some studies suggest that even chronic low doses of THC can help to improve cognitive function — at least in animal models (9). As far as humans are concerned, there is growing data suggesting its positive effects on memory (as mentioned above).
Here’s a summary of the current research:
- A study from the Frontiers in pharmacology has found that CBD promotes neurogenesis — the growth and development of new cells in the brain. Neurogenesis prevents further cognitive deterioration. This specific study analyzed the effects of mice with induced Alzheimer’s condition prior to being treated with CBD. The CBD effectively reversed the cognitive impairments of the mice (10).
- A separate study indicates that an 8-month CBD treatment can prevent the development of social recognition memory deficits. Similar to the previous study, this one was conducted on mice in a controlled laboratory environment (11).
- According to a study from the American Journal of Psychiatry, CBD has a beneficial effect on schizophrenia. The authors claim that CBD’s activity is independent of dopamine receptor antagonism, which makes it a promising treatment for the condition (12).
- The aforementioned Australian review suggested similar health benefits of CBD. After covering 27 publications in peer-reviewed journals, researchers concluded that CBD enhances cognition in “preclinical models of cognitive impairment.” Cognitive impairment examined in the study included disorders such as schizophrenia, Alzheimer’s disease, meningitis, sepsis, malaria, hepatic encephalopathy, and brain ischemia (13).
That being said, we are still lacking clinical evidence on CBD for memory loss, and until more data is collected, we can only theorize about these effects and experiment with CBD on our own. The good news is that all animals share the same endocannabinoid system that responds to plant-based cannabinoids in a similar manner. This means that studies using animal models show a high degree of relevance, and positive results from such research usually give green light to human trials.
Can CBD Cause Short Term Memory Loss?
Perhaps one of the biggest stereotypes surrounding cannabis is that the long-term use of the plant may cause problems with short-term memory due to alleged brain damage.
Now that we’ve established CBD and THC are both antioxidants and neuroprotectants, you may be wondering whether those alleged problems are caused by some other properties of these cannabinoids.
The truth is, CBD doesn’t cause short term memory loss, and as the current evidence suggests, it can actually improve memory and focus, aiding people with cognitive disorders.
It’s the THC that May Cause Short Term Memory Loss… But Here’s The Catch!
When it comes to THC, this issue is less obvious. THC has been shown to cause short-term memory loss directly after use. The results came from adolescents and indicated problems with the ability to recall things. However, these results weren’t replicated in population studies, nor did they carry over to adult samples.
THC has a very similar structure to anandamide, which is one of the two major cannabinoids produced by the body. Anandamide comes from Sanskrit and means “ananda,” which translates to “bliss,” “joy,” and “happiness.”
Aren’t these the feelings you experience after hitting a vape pen with cannabis oil?
Anandamide also plays an important role in the formation and processing of memories. Anandamide deficits are associated with a faster onset of PTSD in people who have gone through trauma; it also causes a person to experience more severe flash-backs from traumatic events. THC happens to alleviate the symptoms of PTSD because it makes the memory more selective.
Now, when the user gets a bit too high for their tolerance, the brain takes it as if there was more anandamide than it actually needs to function on the optimal level. This is when the brain may become more selective than it should.
Ever found yourself in a situation where in the middle of telling a story, you lose a thought and need a few seconds to recall the message you’ve been trying to convey?
That’s the backfiring selectivity of your memory.
It’s not chronic and it stops once your body gets flushed from THC.
How Much CBD Should I Take?
There are no officially established standards for CBD oil when it comes to dosage. All people are different, so the optimal CBD dosage may vary between individuals who are going to take it for a memory boost.
Currently, the U.S. Food and Drug Administration (FDA) doesn’t regulate the safety and purity of dietary supplements. As you may guess, hemp-derived CBD products are categorized as supplements, so you also need to pay attention to the quality of your CBD oil. There are many products out there that contain less CBD than advertised.
But, when you have a high-quality product in your hand, looking for advice on the dosage, here’s one simple advice: start low and go slow.
Different studies recommend starting with 1–50 mg of CBD daily. While 1 mg is rather considered a microdose, most people start with 5–10 mg twice a day. For some people, CBD may provide fast relief, whereas others will need to give it some time to work in the endocannabinoid system. Still, if you don’t feel any difference after a week of testing your dose, increase it by another 5 mg, and monitor the results for next week.
Once you’ve found the amount of CBD that boosts your focus and memory, you can stick to it, as people don’t build a tolerance to CBD. The cannabinoid is even known to induce “reverse tolerance,” where users take less CBD over time due to feeling better.
Final Verdict: Does CBD Oil Really Improve Memory?
CBD oil may be a natural and safe alternative for those seeking help for memory loss. CBD has remarkable antioxidant and neuroprotective effects on the brain, and unlike traditional treatments, its use doesn’t raise safety concerns among patients.
Research from animal models and preliminary human studies has yielded promising results when it comes to the memory-boosting properties of CBD, although we’re still waiting for clinical trials to investigate its efficacy on a large scale. So far, we know that CBD reduces inflammation, curbs oxidative stress, and contributes to neurogenesis in the brain — all of which are essential for memory preservation.
If you’re thinking of adding CBD oil to your supplementation plan, make sure to consult with your doctor to avoid any adverse interactions that CBD may have with your current medication. A visit to a knowledgeable professional will also help you establish an effective dosage range for your individual situation.
Do you take CBD to boost memory? Let us know in the comments below!
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Livvy is a registered nurse (RN) and board-certified nurse midwife (CNM) in the state of New Jersey. After giving birth to her newborn daughter, Livvy stepped down from her full-time position at the Children’s Hospital of New Jersey. This gave her the opportunity to spend more time writing articles on all topics related to pregnancy and prenatal care.
The Impact of Cannabidiol on Human Brain Function: A Systematic Review
Background: Accumulating evidence suggests that the non-intoxicating cannabinoid compound cannabidiol (CBD) may have antipsychotic and anxiolytic properties, and thus may be a promising new agent in the treatment of psychotic and anxiety disorders. However, the neurobiological substrates underlying the potential therapeutic effects of CBD are still unclear. The aim of this systematic review is to provide a detailed and up-to-date systematic literature overview of neuroimaging studies that investigated the acute impact of CBD on human brain function. Methods: Papers published until May 2020 were included from PubMed following a comprehensive search strategy and pre-determined set of criteria for article selection. We included studies that examined the effects of CBD on brain function of healthy volunteers and individuals diagnosed with a psychiatric disorder, comprising both the effects of CBD alone as well as in direct comparison to those induced by ∆9-tetrahydrocannabinol (THC), the main psychoactive component of Cannabis. Results: One-ninety four studies were identified, of which 17 met inclusion criteria. All studies investigated the acute effects of CBD on brain function during resting state or in the context of cognitive tasks. In healthy volunteers, acute CBD enhanced fronto-striatal resting state connectivity, both compared to placebo and THC. Furthermore, CBD modulated brain activity and had opposite effects when compared to THC following task-specific patterns during various cognitive paradigms, such as emotional processing (fronto-temporal), verbal memory (fronto-striatal), response inhibition (fronto-limbic-striatal), and auditory/visual processing (temporo-occipital). In individuals at clinical high risk for psychosis and patients with established psychosis, acute CBD showed intermediate brain activity compared to placebo and healthy controls during cognitive task performance. CBD modulated resting limbic activity in subjects with anxiety and metabolite levels in patients with autism spectrum disorders. Conclusion: Neuroimaging studies have shown that acute CBD induces significant alterations in brain activity and connectivity patterns during resting state and performance of cognitive tasks in both healthy volunteers and patients with a psychiatric disorder. This included modulation of functional networks relevant for psychiatric disorders, possibly reflecting CBD’s therapeutic effects. Future studies should consider replication of findings and enlarge the inclusion of psychiatric patients, combining longer-term CBD treatment with neuroimaging assessments.
Keywords: Cannabis (marijuana); cannabidiol; delta9-tetrahydrocannabinol; functional MRI; neuroimaging.
Copyright © 2021 Batalla, Bos, Postma and Bossong.
Conflict of interest statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.