Are There Any Studies On CBD?
A major obstacle in understanding the possible benefits of CBD is the lack of extensive and definitive research into CBD. There are few clinical trials with CBD about humans; people and the medical community often rely on anecdotal evidence rather than scientific proof about the effectiveness (or not) of CBD.
There are various reasons for this surprising lack of research. For one, all by-products of cannabis such as marijuana and hemp were forbidden for a long time and until quite recently. Scientists and researchers had no access to any material to do their experiments.
Also, the general environment was not propitious to studies into CBD, THC, and other cannabinoids. Since cannabis was considered an illegal drug, there was very little interest in studying its potential contribution to alleviating illnesses.
The effects of legalisation
Things have changed across the world in the last years. CBD has been legalised in the UK—as long as it contains no THC. THC is still a controlled substance under the Misuse of Drugs Act 1971 because it is psychoactive (you can read more on the differences between CBD and THC here).
But even the case of CBD remains complex. Although it is officially legalised, it remains practically controlled. Only specialist doctors can prescribe CBD for specific clinical cases where no other medicine has any effect.
However, there is a technicality in the law. This allows for the sale of CBD on the high street as a nutritional supplement.
Manufacturers and producers of CBD products are using this loophole to produce and promote their CBD products, selling them freely (read more on CBD’s legality in the UK here).
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Are CBD products regulated?
Many CBD products and supplements widely available have questionable contents: since there is no central authority testing CBD products as a nutritional supplement, the quality and purity of these CBD products are not checked.
Research suggests that, in many cases, there is a wide divergence between what the label claims and the actual content in CBD.
Hence, the CBD oil that specialist doctors prescribe for specific medical conditions is quite different from the CBD products that people buy freely on the high street.
All this uncertainty around the legality and availability of CBD has led to an increasing confusion about the actual health benefits of CBD. Websites and individuals have been making wild claims about CBD. This, in turn, has made consumers expect miracles out of taking a few drops of CBD.
CBD has been presented as the ultimate tool to alleviate—or even heal—conditions such as anxiety, depression, rheumatoid arthritis, multiple sclerosis, seizures, Parkinson’s disease, and even cancer. The promise of a medicine with few serious side-effects adds to CBD’s allure as a possible alternative to conventional medicine.
But what is the scientific evidence behind such claims?
What have clinical trials on CBD shown us so far?
With several studies showing that CBD may help alleviate certain ailments, a 2018 meta-study examined previous CBD trials and studies related to CBD and its effect on pain and inflammation. The aim was to evaluate the accuracy of any trial results.
This study concluded there are no “rigorous clinical studies on the issue.”
In assessing the studies, the researchers found there was moderate-quality evidence. Other trials gave limited or weak evidence as to the effectiveness of CBD.
This makes sense. The clinical evidence so far is weak because there is no wide, large-scale, long-term scientific trial to determine the effectiveness of CBD on specific ailments.
The trials so far had various dosages and different forms of CBD administered. This confounds the results, especially since there is evidence that CBD may be biphasic; i.e. a low dose may have the opposite effect from a high one.
CBD oil for anxiety and depression
CBD may have an impact on anxiety and depression because it interacts with the dopamine and serotonin receptors. These are the molecules responsible for mood, behaviour, and cognition.
A 2009 study found that CBD can attenuate stressful responses in rats.
A 2010 study showed that there is a therapeutic potential for anxiety and depression as cannabinoids displayed antipsychotic, anxiolytic, and antidepressant properties.
A study undertaken in 2011 showed that CBD can reduce social anxiety related to public speaking.
A 2013 study on mice suggested the anxiolytic effect of CBD on stressed mice involved the regeneration of cells in the hippocampus part of the brain.
A 2014 study about the anxiety and depression-fighting qualities of cannabidiol and found that when CBD is administered in high concentrations it stimulates a serotonin receptor called 5-HT1A and ultimately alleviates anxiety.
A 2015 study on humans and mice showed that anandamide could be a stimulant for mood enhancement and decrease of fear.
A further 2015 study showed that CBD had a good interaction with the serotonin 5-HT1A receptor.
Another 2015 study researched the endocannabinoid system and how the generation of neurons within it could help in treating anxiety, stress and, depression.
A 2015 study researched how cannabidiol can treat anxiety disorders; it found that preclinical evidence ‘conclusively demonstrates CBD’s efficacy in reducing anxiety behaviors’ with minimal narcotic features and an excellent safety profile.
However, a double-blind study in 2017 showed that CBD does not change a healthy adult’s response to emotional stimuli, therefore suggesting that CBD is ineffective in mood or anxiety problems. This study was performed on healthy adults, so CBD may be helpful in anxious or depressed people but not healthy ones.
Another 2017 study showed that cannabidiol could stop fear memories from consolidating, again in rats.
A further study in 2018 reviewed the neurological benefits of phytocannabinoids and found that they offer a powerful therapeutic potential due to their interaction with our endocannabinoid system. But there need larger and quality clinical trials to prove the results.
A study in 2019 analysed the role of cannabidiol in anxiety and depression. Results showed that CBD was a promising tool for reducing anxiety and depression with fewer side effects than conventional medication.
A 2019 study attempting to confirm anecdotal claims showed that 79.2% of patients taking 25 mg of CBD saw an improvement in their social anxiety symptoms. But there were also 15.3% of patients who said that their symptoms got worse with CBD.
This may be explained by the possibility that CBD is biphasic. That’s why CBD dosage is critical: the effect you get for a low dosage may be the opposite of what you get at a high one.
Another 2019 study declared that “CBD displays promise as a tool for reducing anxiety in clinical populations.” However, randomised and controlled trials are necessary to prove this finding.
Finally, another 2019 study on teenagers with social anxiety established that the “results indicate that CBD could be a useful option to treat social anxiety”.
The consensus is that CBD may be helpful in treating anxiety or depression. However, most research has been done on rats. Other studies included too small a number of participants.
More widespread research with human patients is required to have definitive and large-scale trustworthy results.
CBD oil for insomnia
CBD may work indirectly to treat insomnia by relieving stress and anxiety – the leading causes of sleep problems. It may also work directly by making our endocannabinoid system work better, thus increasing the serotonin and GABA levels in our brain.
A recent study found that there were benefits for people suffering from anxiety-related insomnia. This supports the hypothesis that CBD intervenes indirectly by lowering the levels of anxiety initially. As a secondary effect, this leads to better sleep.
A 2014 study found that CBD was helpful for Parkinson’s sufferers who had REM-related sleeping problems.
A 2017 review of literature concluded that CBD could have therapeutic potential for the treatment of insomnia.
Another recent study, undertaken in 2019, showed that the endocannabinoid system affects the circadian rhythms and hypothesized that external CBD could help in regulating circadian rhythms in aging populations.
There is an ongoing study at a Massachusetts hospital regarding the effectiveness of CBD in treating anxiety. The trial findings could give some helpful pointers regarding the effectiveness of CBD in alleviating anxiety and its ancillary effect, helping with sleep.
Finally, another 2019 study on people suffering from PTSD showed that patients who were given CBD reported a reduction of their PTSD symptoms as well as a reduction of frequent nightmares. As PTSD often leads to insomnia, this may indirectly help alleviate its symptoms.
CBD oil and skin problems
Due to its anti-inflammatory properties, CBD has been suggested as a possible treatment for skin problems such as psoriasis.
A 2007 study showed that CBD had potential therapeutic value in treating psoriasis.
And another study in 2019 asserted that CBD topical creams were effective in improving skin disorders and inflammations. However, the problem with topical creams is that very little CBD can actually reach the deeper levels of the epidermis (read more on CBD topical creams here).
Further studies could be useful in understanding how CBD taken orally can help alleviate skin problems.
CBD and allergies
Because of CBD’s potential anti-inflammatory properties, it is theorised that CBD may help prevent allergies.
A 2009 study concluded that “cannabinoid receptors and their endogenous ligands play a crucial role in the regulation of the immune system.” As allergies are the result of an overreactive immune system, it is possible that this could lead to fewer allergic reactions.
A 2005 research showed that “in the context of the pro-inflammatory function of mast cells, cannabinoids act as potential anti-inflammatory agents.” Mast cells are the one secreting histamines, the compounds causing inflammation in the tissues surrounding the allergen. Stopping them should result in no excessive histamine being discharged in the body, thus alleviating the symptoms of allergic reactions.
A 2018 study showed that CBD was beneficial as an anti-inflammatory when it came to allergic contact dermatitis.
And a 2013 study on guinea pigs concluded that CBD could “influence antigen-induced airway smooth muscle tone suggesting that this molecule may have beneficial effects in the treatment of obstructive airway disorders.” Such disorders are common during allergic reactions.
CBD oil and irritable bowel syndrome
CBD’s potential anti-inflammatory qualities have been at the centre of studies regarding how it could help in easing irritable bowel syndrome symptoms.
Research so far has been promising: a 2008 study concluded that people suffering from IBS—among other conditions—displayed a deficient endocannabinoid system. The study concluded that perhaps CBD could help in replacing or kick-starting our endocannabinoid system.
A 2016 study conducted on mice revealed that CBD could lighten the inflammation related to IBS.
A 2008 review analysed the link between the CB2 receptors and GI inflammation. The role of CB2 receptors in the resolution of GI inflammation offers us interesting insight into the possible role of CBD (which also interacts with the CB2 receptors) in treating IBS.
CBD and gut inflammation
The role of our internal endocannabinoid system in the proper functioning of our GI was also researched in a 2004 study. The result was that there is a close link between our endogenous cannabinoid system and intestinal diseases.
Again, though, a lot of studies were either small-scale or merely suggested that CBD may be beneficial because of the connection of IBS with our endocannabinoid system (read more on CBD and the endocannabinoid system here).
It remains to be seen whether CBD can have an effect on making our endocannabinoid system work better or supplement it.
CBD oil for arthritis
Arthritis sufferers often have to take medicine with serious side-effects. The potential of alleviating arthritis with CBD is something that sufferers are looking into with extreme interest.
Again, it is the anti-inflammatory qualities of CBD that have attracted the most attention in medical trials. Starting with topical CBD creams for arthritis, a study in 2016 showed that topical CBD creams had therapeutic potential for relieving arthritis-pain in rats.
Another study analysed the existence of CB1 and CB2 receptors in arthritic rats’ joints. This study showed that these two receptors were involved in arthritis and suggested further studies involving CBD should be conducted.
CBD oil and multiple sclerosis
Inflammation can appear in many forms, arthritis being just one of many.
There is ongoing research on the effectiveness of CBD on inflammation of any sort.
A promising study concerned CBD and Multiple Sclerosis (MS). This study showed that CB2 receptors counteract the inflammation of nerve cells, which is the cause of MS. This looks promising for the use of CBD which interacts with CB2 receptors.
Sativex is the first cannabis-based medicine to be legal in the UK even though it contains both CBD and THC. Sativex is prescribed for multiple sclerosis spasticity. Interestingly, while accepting its health benefits, the NHS considers it cost-ineffective and limits patients’ access to it.
CBD oil and pain management
Pain management is something that many patients experiencing inflammation have to endure.
Sometimes, sufferers opt for opioids to reduce their pain levels. Due to the acute opioid crisis in the United States, researchers are trying to find whether CBD can be a good alternative to opioids in pain management.
The interest is intense because CBD is believed to not be addictive (due to the lack of THC) and has few reported side-effects (read more on CBD’s side-effects here).
An initial double-blind study suggested CBD reduced cravings for opioids. Further studies in 2000 and 2013 showed that CBD may be effective in pain management. This is further supported by a 2015 study that examined how CBD affects inflammation and pain-related behaviour in rats.
A 2009 study about the analgesic potential of cannabis showed that animal studies were displaying efficacy of cannabinoids as an analgesic and that it was promising for severe pain.
A more specialized study in 2019 about pharmaceutical-grade cannabis as an analgesic for fibromyalgia produced promising results after a single inhalation.
Another trial in 2011 showed that “the use of cannabis was associated with beneficial effects on some fibromyalgia symptoms.”
In a systematic review on 1219 patients suffering from neuropathic pain, “patients who received selective cannabinoids reported a significant, but clinically small, reduction in mean numerical rating scale pain scores.”
Another randomized controlled trial in 2015 produced encouraging results that showed “cannabinoids are safe, modestly effective analgesics that provide a reasonable therapeutic option in the management of chronic non-cancer pain.”
CBD oil and epilepsy
It is in the area of epilepsy that CBD has shown the most promising proven results.
The United States’ FDA approved Epidiolex in June 2018, which is a solution containing CBD.
Research had shown that CBD is effective in diminishing the number and severity of epilepsy seizures for people having either Lennox-Gastaut syndrome or Dravet syndrome.
Several studies have shown that CBD can reduce the frequency of seizures—by 43.9% in one case. Another study in 2017 showed that people suffering from refractory epilepsies saw their seizures diminish by 40% when taking CBD.
The UK, along with the rest of Europe, is about to approve Epidyolex, since the European Medicines Association allowed it for seizures. The National Institute for Health and Care Excellence (NICE) has approved Epidyolex for treating these two types of epilepsy.
According to the trials done by GW Pharmaceuticals, the producers of Epidyolex:
- 47% of patients experienced a ≥50% reduction in seizures after 12 weeks of treatment.
- The positive clinical effects were maintained for 36 weeks of treatment.
- There was a median reduction in total seizures of 45% across all patients.
- Only 4% of patients had to withdraw due to side-effects.
However, it is yet unclear how CBD actually diminishes seizures. Researchers are still trying to understand the process through which CBD acts in the body.
CBD and Parkinson’s
There is still a lot to understand, research, and analyse regarding how CBD acts.
Parkinson’s UK, the largest charitable institution studying and researching Parkinson’s, has launched a £1.2 million first-ever clinical trial on the possible effectiveness of CBD in treating or alleviating Parkinson’s symptoms. The study will extend over four years and will be a double-blind, placebo-controlled study.
In particular, researchers specifically want to evaluate the benefits of CBD in treating the psychosis, hallucinations, and delusions associated with Parkinson’s. Moreover, researchers want to see whether administering CBD at the early stages of Parkinson’s when the psychosis symptoms appear, can delay the development of the condition.
If CBD can delay or alleviate the decreased motor movement associated with Parkinson’s, it would mean a vast improvement in the quality of life for millions.
CBD and alcohol
A 1979 small study separated participants into three groups where they administered CBD and alcohol, separately and in combination. The combination of alcohol plus CBD resulted in significantly lower blood alcohol levels compared to alcohol given alone.
A 2005 clinical study supported the role of “CBD as an in vivo neuroprotectant and shows the efficacy of lipophilic antioxidants in preventing binge ethanol-induced brain injury.” In other words, CBD may prevent brain damage from alcohol.
A 2013 study showed that “transdermal delivery of cannabidiol attenuates binge alcohol-induced neurodegeneration” in mice. The study showed there was a “48.8% reduction in neurodegeneration in the entorhinal cortex.”
A 2014 study found that CBD could protect the liver from alcohol damage in mice. CBD has been found to have antioxidant qualities, fighting oxidative stress. Oxidative stress is involved in alcohol-induced liver damage.
A 2018 preclinical proof-of-principle study showed that “CBD attenuated context-induced and stress-induced drug seeking without tolerance, sedative effects, or interference with normal motivated behaviour.” Drug and alcohol addiction are similar in how they affect the brain, therefore, this is a promising proof of principle that CBD might help with alcohol addiction.
A further 2019 study examined previous findings on CBD’s ability to prevent neurodegeneration. It found that “CBD attenuates cue-elicited and stress-elicited alcohol-seeking, alcohol self-administration [and] withdrawal-induced convulsions.” Based on this finding, CBD might be a potential treatment for alcohol addiction. It also concluded that “CBD was found to exert a neuroprotective effect against adverse alcohol consequences on the hippocampus.”
CBD for pets
A 2016 small study showed the CBD had positive effects on dogs with osteoarthritis or epilepsy. The researcher who undertook this study was given a $350,000 grant from the American Kennel Club to start a study specifically examining the effectiveness of CBD for epilepsy in treatment-resistant dogs.
Another study, conducted in 2018, showed that osteoarthritic dogs taking CBD displayed a significant decrease in canine brief pain inventory and an increase in Hudson activity scores without side effects. The study concluded that taking CBD could increase comfort and ability in osteoarthritic dogs.
A 2019 study on the effects of CBD on epileptic dogs stated that dogs had a reduction in the number of seizures when taking CBD and their anti-epileptic medicine. But dogs in the placebo group also showed a decrease in symptoms, therefore the study concluded that more research is necessary.
A study undertaken by the Beckley/Exeter Cannabis Centre at the University of Exeter is investigating the potential of CBD in tobacco cessation.
This study is also researching other cannabinoids, apart from CBD, and their potential in treating various diseases and conditions.
The growing interest in CBD and its speculated health benefits are leading the medical community and researchers into studying the real effects of CBD on various illnesses, conditions, and diseases.
The fact that we have an endocannabinoid system that interacts with CBD has triggered the interest of the medical community in researching CBD and its potential. However, it’s still too early to reach any definitive conclusions.
Are there any studies on CBD?
If you’re still asking yourself, “are there any studies on CBD,” the answer is clear: several, many of which show promising results.
However, the trials need to be undertaken on a grand-scale and long-term basis on human patients. The dosages, forms of administration, and other important aspects have to be carefully appraised. Only then will there be no variations or differentiations that could skew the results.
Until such scientific evidence is available, the market of CBD nutritional supplements should be regulated because the CBD products currently available on the high street are often mislabelled.
In the meantime, consumers of CBD should be careful about any extravagant claims CBD manufacturers present. Remember that there is no clear and definitive scientific proof of CBD’s medical benefits yet, with the exception of CBD for particular epilepsy conditions.
If you wish to try CBD, remember to consult your doctor first, as CBD can interact with certain conditions or medication. Also, you may need your doctor’s help to determine the right CBD dosage for you. Finally, not all CBD products are the same. You can read some tips on how to choose a trustworthy CBD provider here.