EducationThe science behind THC oil for depression symptom relief

The science behind THC oil for depression symptom relief

9 min read

Sam North

The science behind THC oil for depression symptom relief


Diagnoses of clinical depression are at an all-time high here in the UK. The COVID-19 pandemic brought with it a sharp hike in rates of both depression and anxiety – and while that period is, thankfully, slowly passing, life is still fraught with many challenges and uncertainties.

Over 20% of the UK adult population is now dealing with depression. That's a surprisingly substantial number. There are many forms of depression, with symptoms ranging from fatigue and irritability to feelings of hopelessness, self-loathing, guilt, and worthlessness.

Obviously, the need for new, complementary treatment options for depression has never been more pronounced. Conventional approaches such as psychotherapy and antidepressant medications are still indispensable in the treatment of clinical depression, but there is increasing interest and demand in exploring other potential remedies that may be added to a holistic treatment plan. Among these new options is medical cannabis.

Enter THC Oil. THC is the most abundant cannabinoid in most cannabis cultivars, and the compound responsible for the intoxicating effect of the plant. But new research shows that THC could be a potential ally in the battle against depression, and with possibly fewer negative side effects than some of the heavy pharmaceutical options that are currently prescribed.

Let's have a look at the pros and cons of taking THC oil for depression treatment, and delve deep into all the currently available research relating to cannabinoid administration for the reduction of depression symptoms.

Understanding THC oil

While most people associate recreational cannabis use with smoking, there is now a growing movement of people consuming cannabis through other delivery methods, such as tinctures or edibles. One of the most popular administration methods, especially in medicinal settings, is THC oil taken either sublingually or added to food and drink.

What is THC oil exactly?

THC oil is a product that contains a concentrated form of tetrahydrocannabinol (THC), when compared to dried cannabis flower options. It is extracted from cannabis plants and then mixed with carrier oil – usually MCT oil. There are different THC concentrations available on the medicinal market, with all medical products displaying a THC mg per ml concentration as a dosage guide.

How do cannabinoids work with the body?

THC is able to affect the body due to the fact that it can interact with the endocannabinoid system (ECS).

The ECS is a vast interconnected network of receptors (CB1 and CB2), signalling molecules (our own endocannabinoids), and enzymes that are found throughout the entire body and brain. It is directly responsible for regulating a huge number of both physiological and psychological processes and is essential in helping the body maintain homeostasis.

THC is a phytocannabinoid (a cannabinoid produced outside the human body) that is able to interact with the ECS in a variety of ways due to the fact the chemical structure closely resembles an endocannabinoid. It has been found to have both direct and indirect effects on the CB1 receptor, and may even be able to increase the levels of certain endocannabinoids.

Research on THC Oil and Depression

Before we dive into what the current science is saying about THC oil and depression, we should make one caveat clear. 

Medicinal cannabis products should never be thought of as a ‘cure-all’ for depression – they are not. Rather, we should view THC oil (and other cannabis products) as a potential tool that may be a very beneficial addition to your overall treatment strategy.

It is also good to point out that while THC has been researched since the 1970s, and also that the legality of cannabis is finally changing in many countries, research into the therapeutic effects of THC remains limited and more trials are needed to confirm findings. For more than a century, international drug laws have severely impeded scientists' access to cannabis to perform meaningful trials on its medicinal properties, and this has only recently begun to change.

That being said, there are some interesting research papers and clinical trials we can explore.

This study from 2021, titled “Antidepressant and Anxiolytic Effects of Medicinal Cannabis Use in an Observational Trial” looked at a wide range of the effects of different cannabis products. 

THC dominant, CBD dominant, and products with a balanced ratio of THC/CBD were all offered to participants, with the three options offering varying degrees of antidepressant or depression symptom-reducing qualities. 

The results showed that “Cannabis Users reported lower baseline depression, and were also more likely to present below the cut-off for clinical concern for depression”, but also found that this effect was strongest among participants using CBD-dominant products. Follow-up analysis also showed, “participants who initiated medicinal cannabis use during the follow-up period showed a significant reduction in both depression and anxiety symptoms.”

Another study, this time from 2018, showed that cannabinoid therapy could be applied to potentially reduce the symptomatic effects of depression. It found that products containing a low dose of THC with higher levels of CBD were the best option "for reducing perceived symptoms of depression", whereas high THC/high CBD cannabis was best for reducing stress.

The last piece of scientific evidence that we are going to look at is a retrospective study of patients utilizing medical cannabis from Canada in 2022. 

This was a large-scale endeavour, with more than 7300 participants. It found that both anxiety and depression were greatly reduced in patients taking cannabis as part of their treatment regimen, stating "This study provides some evidence to support the effectiveness of medical cannabis as a treatment for anxiety and depression”.

Unfortunately, the study did not specify which cannabinoids were being used, so it is uncertain if the effects are largely attributed to THC or CBD, or a combination of both.

The difference between CBD and THC

It's important to understand the difference between CBD and THC when discussing medicinal cannabis. While both cannabinoids have been shown, in numerous studies, to be potentially beneficial for mental health, all prospective medicinal cannabis patients should fully understand the differences between them.

CBD, unlike THC, is a non-intoxicating compound. This means that it can be taken in much larger quantities while not producing any of the 'high' associated with cannabis. As such, it's an attractive option for those seeking the health benefits of cannabis while still being able to function normally.

Research suggests that CBD is potentially highly effective at reducing the symptoms of both anxiety and depression, particularly when combined with certain terpenes.

Terpenes and depression

Gone are the days when cannabis could simply be split into the general Sativa and Indica groupings. The newest research is pointing to the fact that the effects offered by certain strains are due to the 'entourage effect' of the entire cannabinoid and terpene profile working together in harmony, and not just the THC and CBD content.

Terpenes are the building blocks of essential oils and have been applied in traditional medicine for centuries. There are hundreds of different terpenes, and each one offers its own unique benefits when combined with other cannabinoids.

There are numerous terpenes that have been identified as offering antidepressant qualities, such as myrcene, limonene, pinene, nerolidol, beta-caryophyllene, and linalool. The new school of medicinal cannabis thinking is that by choosing cannabis products that naturally offer a terpene profile containing these options, it's possible to gain an even stronger potential antidepressant effect.

How to take THC Oil for depression

As we have mentioned, the most current research is pointing to products that contain low doses of THC with higher doses of CBD to be most effective for reducing depressive symptoms

A low dose of THC is considered to be around the 2 mg mark, but this varies greatly depending on your individual physiology, your tolerance level, and the type of product you are administering. It is not recommended for patients that are just beginning their medicinal cannabis journey to take more than 10 mg of THC in a single dose.

The method of consumption is also a factor that needs to be considered. In general, vaporizing cannabis offers a more rapid effect than edibles, but many people simply dislike the idea of vaping and prefer the convenience and discretion of edibles. Edibles (THC oil included) offer a much slower onset, but also a longer duration of effect.

Tinctures and oils offer a happy middle ground when taken sublingually. Sublingual application refers to taking a drop of tincture or oil under the tongue. This offers much faster effects than an edible and is easier to control dosage-wise than vaping.

It's important to grasp that, as with any medication, it is essential that you first seek professional healthcare advice before starting any type of medicinal cannabis regimen. It is also good to understand that there are certain risks associated with using cannabis as a treatment for depression and other mental health conditions. These include the potential for dependency and increased risk of psychosis.

It's also worth noting that, despite numerous studies pointing to cannabis as a potentially effective therapy option, only further research will have the power to validate these theories. Until then, it is essential that anyone seeking relief through medicinal cannabis does so responsibly and in conjunction with professional medical advice.

The bottom line

By understanding the difference between CBD and THC, researching which terpenes are most effective for reducing the symptoms of depression, and consulting with an experienced healthcare professional, it is possible to find the most suitable and effective medical cannabis regimen for treating your symptoms of depression.

Releaf understands the importance of medical cannabis in treating various medical conditions. With our tailored monthly packages, specialist consultations for medical cannabis, and a unique medical cannabis card for protection, you can access the treatment you need without worrying about the stigma. 

Releaf - Removing the Stigma from Medical Cannabis

It is important to seek medical advice before starting any new treatments. The patient advisors at Releaf are available to provide expert advice and support. Alternatively, click here to book a consultation with one of our specialist doctors.

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Sam North, a seasoned writer with over five years' experience and expertise in medicinal cannabis, brings clarity to complex concepts, focusing on education and informed use.

Our articles are written by experts and reviewed by medical professionals or compliance specialists. Adhering to stringent sourcing guidelines, we reference peer-reviewed studies and scholarly research. View our editorial policy.

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How long does it take to feel the effects of THC oil?

The time it takes for you to feel the effects of THC depends on the methods of administration as well as your own physiology. Fortunately, there are fast and slow-acting options, as well as ways to take low or high doses in order to facilitate control over the way your body reacts to your medicine.

Editorial Team