Can cannabis help your mental health? Everything you need to know

With the prevalence of poor mental health on the rise, many people are finding cannabis helpful for managing symptoms of common disorders such as depression, anxiety and PTSD.

We explore its role in mental health treatment in more detail. 

All of us have ‘mental health’ – not just those with a diagnosed condition – and it’s important we take measures to look after it, just as we do our physical health. 

But mental illness is becoming increasingly more prevalent among the general population, heightened by the stressors of the coronavirus pandemic and more recently, the ongoing cost-of-living crisis. 

According to Mind, one in four people in England will experience a mental health problem of some kind each year. 

A recent survey conducted by Gov.uk between September-October 2022, found that around one in six (16%) adults experienced moderate to severe depressive symptoms; higher than pre-pandemic levels (10%).

The findings also suggest that the cost-of-living crisis and rising household bills are having a significant impact on the mental health of the population.

Mental illness covers a broad range of disorders. From generalised anxiety and depression to post-traumatic stress disorder (PTSD), eating disorders, obsessive-compulsive disorders (OCD), borderline personality disorders and bipolar disorder.

With such a wide range of issues, and often an overlap of multiple diagnoses, how they are treated can vary widely, although treatment plans commonly include medications such as selective serotonin re-uptake inhibitors (SSRIs) in combination with talking therapies.

The role of cannabis in mental health treatment

There has long been a stigma associated with cannabis and mental health, but many patients in the UK are now prescribed it legally for a range of psychiatric conditions. 

In fact, after chronic pain, anxiety is the second most common indication prescribed for, according to the figures from the UK’s observational study, Project Twenty21. 

Other mental health conditions which cannabis is prescribed for include post traumatic stress disorder (PTSD), depression, substance use disorder and insomnia, alongside neurological and neurodivergent disorders such as Tourette’s, autism and ADHD. However, it is important to note that someone with a previous history of psychosis or schizophrenia may not be suitable for a cannabis prescription. 

You can find a full list of psychiatric conditions for which cannabis is prescribed here.

So how does it work?

Cannabis comprises over 500 compounds, including cannabinoids, terpenes, flavonoids, oils, and many more. The most researched chemical compounds are cannabinoids and terpenes.

THC and CBD are the most abundant cannabinoids in cannabis and are known to interact with the human endocannabinoid system (ECS) on various levels to bring about homeostasis, or balance, in the body.

The ECS is a cell signalling system that consists of various enzymes, endocannabinoids and receptors, and these components work in synergy to ensure that different components of the body (for example the cardiovascular, immune, digestive and nervous systems) function seamlessly.

CBD directly interacts with the ECS, through which it can have a beneficial effect on inflammation, mood stability and sleep. It is also thought to affect the amygdala, the part of the brain that controls an individual’s emotions, motivation and emotional behaviours. CBD works with the ECS to decrease activity from the amygdala, thus potentially keeping anxiety-related conditions at bay.

What about THC?

THC also has a role to play in mental healthcare. While consuming too much can aggravate anxiety, the correct therapeutic dose can actually help mitigate some symptoms, particularly those related to PTSD.

THC binds to the CB1 receptors in the brain, which are vital for regulating anxiety and sleep. It is also thought to reduce REM sleep, which causes intense dreams, making it helpful for patients experiencing nightmares, intrusive thoughts and flashbacks as a result of PTSD.

People with PTSD have been shown to have a higher number of CB1 receptors, because they have lower circulating levels of anandamide in their blood. As a result, the brain has to compensate and expands the number of CB1 receptors, which THC binds to.

A double blind placebo controlled trial, published in November 2022, concluded that THC may prove to be a beneficial pharmacological treatment for PTSD, when used in conjunction with cognitive reappraisal therapy.

Dr Niraj Singh, a consultant psychiatrist and medical cannabis prescriber, says it is important that patients and prescribers ‘start low and go slow’ to find what works for the individual.

THC is only legal in the UK when on prescription and currently this is only accessible through one of the private clinics. This also ensures that you have access to clinical guidance and oversight to reduce the risk of any unwanted effects.  

What does the research say?

While there is limited clinical evidence so far, there is an abundance of real-world data.

In the UK, T21 revealed last year that 86% of patients reported an improvement in anxiety or depression after three months of medical cannabis treatment. The UK Medical Cannabis Patient Registry also found statistically significant improvements in anxiety, pain and sleep quality scores as well as general quality of life at one and three months following treatment. 

A study published in 2020 demonstrated that CBD-containing compounds were helpful in alleviating psychotic symptoms and cognitive impairment in patients with a variety of conditions such as social anxiety disorder, as well for anxiety, bipolar disorder and PTSD, although admittedly this evidence was weaker.

More recently, a pilot study led by Orygen, an Australian organisation offering support for young people’s mental health, found that young people with treatment-resistant anxiety had an average 42.6% reduction in their condition’s severity and impairment following 12 weeks of treatment with CBD.

In what is thought to be the largest dataset of its kind, Canadian researchers surveyed over 7,000 patients authorised to access medical cannabis products. According to their findings, published in 2022 in the journal Psychiatry Research, patients with symptoms of anxiety and/or depression reported sustained improvements following the use of cannabis.

Elsewhere, researchers at Washington State University have analysed data from hundreds of people who recorded their symptoms before and after cannabis consumption using the tracking app Strainprint.

Their findings showed that in people who self-reported as having PTSD, cannabis reduced the severity of intrusive thoughts by about 62%; flashbacks by 51%, irritability by 67% and anxiety by 57%.

A follow-up study, published in October, reported that users with OCD reported that cannabis reduced their compulsions by 60%, intrusions, or unwanted thoughts, by 49% and anxiety by 52%.

The studies have also looked at a number of variables but rarely found differences in the efficacy of cannabis with differing levels of THC and CBD – apart from in depression where a lower level of THC and higher CBD seemed to be most effective in reducing symptoms. However, researchers did warn that cannabis may not be a long-term solution.

There is some evidence for its use in Tourette’s syndrome too, with a number of papers having been published with encouraging results.  Although small, one study from 2017 reported that 18 out of 19 participants were “much improved”, and their tics scores decreased by 60%, while a six-week randomised control trial from 2003 concluded that THC is “effective and safe” in the treatment of tics. 

While more evidence is needed, many of those who are currently using medical cannabis report huge improvements in mental health symptoms and their overall quality of life.

Consuming responsibly 

Anxiety and paranoia are two typical hallmarks of negative cannabis side effects. These symptoms can be mild for some or more drastic in the case of vulnerable populations, like those with certain mental health disorders.

It’s always important to be aware of the side effects of cannabis to ensure you can make more informed decisions about your consumption. If you are experiencing any adverse effects or feel like it’s starting to have a negative impact on your mood, it may be time to take a tolerance break.

DISCLAIMER: This article is intended for educational purposes only, always speak to your doctor before making any changes to your medical care.

If you need support with your mental health, there is always someone you can talk to.

Contact: Mind  Tel: 0300 123 3393 / info@mind.org.uk/ Samaritans Tel: 116 123 / jo@samaritans.org

READ MORE: How to access a medical cannabis prescription in the UK: step-by-step

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