Medicinal cannabis and anxiety, explained

Anxiety is an extremely prevalent mental health condition affecting millions of Australians daily. With symptoms ranging from excessive worry and restlessness to panic attacks and sleep disturbance, it’s no wonder so many Australians are turning to a wide range of therapies to help manage their condition.

Anxiety is among the top conditions that cannabis is prescribed to help treat in Australia.¹ In this article, we’ll break down why medicinal cannabis is becoming such a popular prescribed treatment for anxiety and how it can help reduce anxiety symptoms in some patients.

What is anxiety?

Anxiety is the body’s physical response to a real or perceived threat. Everyone experiences anxiety from time to time, it can even help us avoid danger in some real-life situations. But for some people, anxious feelings and symptoms don’t go away. They stick around even when there is no real or immediate threat to that person. Anxiety can affect concentration, sleep, relationships and the ability to carry out daily tasks. When anxiety is a problem that persists without the presence of a real or immediate threat, it is generally categorised as an anxiety disorder.

Anxiety disorders are the most common group of mental health conditions in Australia and affect 1 in 4 Australians² at some stage in their life.

The common types of anxiety disorders are:

• Generalised anxiety disorder
• Social phobia or social anxiety disorder
• Panic disorder
• Agoraphobia
• Specific phobias
• Obsessive-compulsive disorder (OCD)
• Post-traumatic stress disorder (PTSD)

In some people, anxiety may also be linked to an underlying health issue. For some, this may mean anxiety signs and symptoms are the first indicators of a medical illness. Conditions associated with anxiety can include chronic pain, IBS, drug or alcohol dependence or withdrawal, thyroid problems, heart disease and diabetes. Certain medications can also cause anxiety in some people.

What are the symptoms of anxiety?

Some of the physical symptoms of anxiety can include:

• Panic attacks
• Shortness of breath
• Heart palpitations
• Dizziness
• Excessive sweating
• Sleep issues
• Stomach issues
• Lightheadedness 
• Dizziness
• Trembling
• + more

People who have anxiety may also avoid certain situations, such as crowds or social events, and may experience constant feelings of fear, racing thoughts, difficulty concentrating and memory disturbances.

Anxiety symptoms may also vary depending on the type of anxiety disorder someone has, for example:

• Generalised anxiety disorder may cause excessive worry about a range of issues such as health, work or finances.
• Social phobia or social anxiety disorder often causes people to avoid social or performance situations for fear of being embarrassed or rejected.
• Panic disorder can cause regular panic attacks, which are sudden intense episodes of irrational fear, shortness of breath, dizziness and other physical symptoms.
• Agoraphobia leads people to avoid certain situations due to fear of having a panic attack (often associated with panic disorder).
• Specific phobias will cause anxiety symptoms in one particular situation or context, such as a fear of animals, insects, places or people. 
• Obsessive-compulsive disorder (OCD) causes unwanted thoughts and impulses, causing repetitive, routine behaviours as a way of coping with anxiety.
• Post-traumatic stress disorder (PTSD) leads to persistent feelings of fear or avoidance that do not fade after experiencing or witnessing a traumatic life event. PTSD symptoms can include upsetting memories, hypervigilance, flashbacks, nightmares and difficulties sleeping.

Source: HealthyWA, Department of Health

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How is anxiety typically treated?

Treatments for anxiety should be dependent on the individual needs of each patient, as well as the type and severity of the anxiety they experience. Anxiety treatment may include psychological therapy, lifestyle changes (including sleep, nutrition and exercise), meditation and mindfulness and/or medication, or any combination of those treatments.

The Royal Australian & New Zealand College of Psychiatrists recommends cognitive behavioural therapy (CBT) as the first line treatment for generalised anxiety disorder, panic disorder and social anxiety disorder.¹⁴ Research shows that CBT is one of the most effective treatments for anxiety, and for preventing future anxiety.¹⁵ CBT treatment involves implementing strategies to change unhelpful thinking patterns and behaviours. It is generally conducted by a trained therapist over 6 sessions or more, and may be used alongside other therapy types, such as exposure therapy or interpersonal therapy.

Pharmacological treatments like antidepressants and tranquillisers are also commonly prescribed to treat symptoms of severe anxiety, panic and stress. For some patients, these medications can be extremely valuable and even life-saving. They can help your patients go about their lives and participate in situations that their anxiety previously prevented. But for others, these treatments come with a wide range of unwanted side effects that make them intolerable. 

These can include:

Potential adverse side effects of antidepressants: 

• Sleep disturbance
• Changes in sexual function / desire
• Loss of full range of emotions
• Tremors
• Weight gain
• Constipation

‍Potential adverse side effects of long-term use of tranquilisers

• Impaired learning
• Increased depression
• Memory loss
• Increased risk of dementia
• Increased risk of death (due to tranquiliser’s impact on respiratory drive in brainstem)

The range of negative side effects that standard pharmacological treatments for anxiety can elicit in some patients has led many to seek alternative medicines and options for treatment, from herbal solutions like kava, ashwagandha and lavender supplements to alternative prescriptions like medicinal cannabis.

Can cannabis help treat anxiety?

Anxiety is the second most common condition³ that medicinal cannabis (sometimes referred to as ‘medical marijuana’, learn about the history and implications of this term here) is prescribed to treat in Australia. Both THC- and CBD-dominant cannabis treatments are prescribed to help treat symptoms of anxiety. A 2018–2019 survey⁴ of 1388 Australian respondents who were self-medicating with (mostly illicit) cannabis also found anxiety to be the most common ‘main condition’ being treated with cannabis. 

While there is conflicting information surrounding cannabis and anxiety, we know that many patients benefit from using medicinal cannabis to treat their anxiety and those that do maintain an ongoing medicinal cannabis treatment plan for anxiety do so because they prefer these treatments to standard or conventional treatments they have previously tried. 

For others, cannabis may not be an effective treatment for anxiety or it may even increase anxiety in some patients. It comes down to the individual, the type and severity of the anxiety, and the type of cannabis medication prescribed to that patient.

One rationale for the use of medicinal cannabis for treating anxiety symptoms stems from the way cannabis interacts with the body’s endocannabinoid system (ECS). The ECS is a biological system present in all humans (and nearly all animals) which regulates numerous physiological processes including mood, appetite, sleep, cognition and immune function.

Our ECS and the physiological processes it regulates can be supported through a range of methods and lifestyle changes, including eating foods rich in omega-3 fatty acids, drinking less alcohol and consuming cannabinoids. Preclinical research⁵ also suggests that the phytocannabinoids found in cannabis (including THC and CBD) can support the production and release of endocannabinoids which may have efficacy in treating anxiety disorders. However, more clinical research is required in this area. 

Does CBD help with anxiety?

CBD and CBD oil treatments may help manage the symptoms of anxiety in some patients. CBD has been shown to have anxiolytic (anxiety reducing) potential in numerous studies, including a 2015 review⁶ of 49 primary preclinical, clinical, or epidemiological studies supporting CBD as a treatment for generalised anxiety disorder, panic disorder, social anxiety disorder, obsessive-compulsive disorder, and post-traumatic stress disorder when administered acutely.

This study’s preclinical evidence conclusively demonstrated CBD’s efficacy in reducing anxiety behaviours relevant to the above anxiety disorders with a notable lack of anxiogenic (anxiety causing) effects. 

In 2022, the Cannabidiol Youth Anxiety Pilot Study⁷ conducted by Orygen also found that CBD may be effective in halving the severity of symptoms and impairment caused by chronic anxiety. The study involved 31 participants aged 12–25 who were recruited from Orygen’s primary care services. The participants had a diagnosed anxiety disorder and had failed to show significant improvement in anxiety severity following at least five cognitive behavioural therapy (CBT) sessions.

“Young people with treatment-resistant anxiety had an average 42.6 per cent reduction in anxiety severity and impairment following 12 weeks’ treatment with cannabidiol – a non-intoxicating component of the Cannabis sativa plant which is often referred to as CBD.”

– Orygen, 2022

Orygen’s pilot study found that CBD not only helped to reduce anxiety symptoms, but was also very well tolerated. They noted that they “did not see side-effects like suicidal thoughts, irritability or sleep problems, which are not uncommon in people taking SSRIs.”

CBD works to reduce anxiety in a number of ways. It can activate serotonin receptors,⁸ modulate the potential anxiety-inducing effects of THC (thanks to the entourage effect) and reduce the fatty acid amide hydrolase enzyme⁹ that breaks down one of the body’s own important endocannabinoids – anandamide – which stimulates feelings of happiness and mental wellbeing. Anandamide deficiency has been shown to be a predictor of stress-induced anxiety, with decreased anandamide corresponding to increased anxiety-like behaviours in some patients.¹⁰ So CBD’s ability to prevent a decrease in anandamide levels makes it a promising treatment for anxiety disorders.

Like with any medication, the effects of CBD will vary depending on the individual and the dose taken.

Does THC help with anxiety?

Like CBD, THC has been shown to have the potential to treat anxiety in some patients, depending on the individual and the prescribed dosage. A 2019 analysis of 83 eligible studies¹¹ found that ‘pharmaceutical THC (with or without CBD) improved anxiety symptoms among individuals with other medical conditions (primarily chronic non-cancer pain and multiple sclerosis).’ While another 2019 review¹² of the evidence supporting the use of THC in PTSD found emerging evidence for positive effects on sleep, nightmares and global PTSD symptoms.

So while there is less evidence to support the use of THC-dominant formulations for anxiety disorders, there is stronger emerging evidence supporting its use in patients with PTSD, as well as anecdotal patient accounts of THC’s efficacy in treating anxiety symptoms.

Unlike CBD which works indirectly with the endocannabinoid system (ECS) and the body’s cannabinoid receptors, THC acts directly upon the body’s ECS¹³ by stimulating cannabinoid receptors (CB1 and CB2). Because the ECS is responsible for maintaining balance and harmony in the body, the effects of THC will be dose-dependent.

Meaning the correct dose of THC can help create balance, while too much THC can cause an imbalance (and potentially increase anxiety) in some patients. With the help of an experienced healthcare practitioner the therapeutic benefits of medicinal cannabis for anxiety can be achieved by finding the right dose of THC for an individual patient.

It’s important to note that THC can exacerbate anxiety under some conditions and in some patients, and that there are driving restrictions for patients taking THC medications.

Can terpenes in cannabis help with anxiety?

Terpenes are the organic, aromatic compounds found in plants in the form of oils. Essentially, they are what gives a plant its unique flavour and aroma. The cannabis plant alone contains more than 150 terpenes. But beyond just influencing the cannabis plant’s unique taste and smell, terpenes also play a significant role in the therapeutic effects of cannabis by interacting with cannabinoids and other cannabis compounds to create subtle differences in our experience.

On their own, there are a number of terpenes which can reduce anxiety, including linalool (found in lavender, rose and basil), limonene (found in lemon and citrus fruits), beta-caryophyllene (found in black pepper and cloves), myrcene (found in mango, thyme and lemongrass) and more. Each of these terpenes (and many more) can also be found in the cannabis plant. And by interacting with the range of cannabinoids and other compounds found within cannabis, terpenes can create or emphasise particular medicinal or other types of effects, opening up a world of therapeutic combinations for anxiety and many other conditions (again, thanks to the entourage effect).

You can help your patients to choose an appropriate medicinal cannabis treatment based on the terpene profile of the medication, and the effects these terpenes can have on the patient’s specific symptom or condition. 

Can cannabis cause or increase anxiety?

Now that we know medical cannabis has the potential to help treat anxiety in some patients, you might be wondering whether cannabis can actually cause or increase anxiety in other patients. 

The simple answer is: yes, cannabis has the potential to cause or increase anxiety in some patients, depending on the type and dose of cannabis administered. 

Let’s break this down into CBD and THC:

CBD → CBD is a known anxiolytic. Meaning it reduces anxiety with a lack of anxiogenic (anxiety causing) effects. CBD has a narrow side effect profile and does not cause the ‘high’ or any of the impairing effects that are typically associated with certain doses of THC. For these reasons, CBD is not a cannabinoid that is generally known to cause anxiety when taken at recommended doses.

THC → THC is also commonly prescribed to treat anxiety disorders and has been shown to be effective for sleep, relaxation and PTSD. But because THC interacts so directly with the cannabinoid receptors within the endocannabinoid system, it has a stronger impact on the body’s ability to regulate anxiety and may even cause or increase anxiety in some patients when taken at too high a dose.

With your help, patients can mitigate these side effects by finding the correct product, strain and dose to achieve reduced anxiety levels through their medicinal cannabis treatment plan. But as with any medication or treatment plan, results and side effects will vary depending on the individual patient.  

What are the most popular cannabis formats to prescribe for anxiety? 

Due to the individual effects medicinal cannabis can have on each patient, it is not a one-size-its-all approach. Meaning, it’s important that you take a unique approach to treating each individual medicinal cannabis patient.

Some examples of how you may choose to prescribe medicinal cannabis to help treat anxiety include: 

Oral cannabis formats (oils, capsules, tablets, pastilles): Often prescribed for ongoing anxiety and may contain just CBD or a combination of THC and CBD and other cannabis compounds such as terpenes. It’s common for some doctors to prescribe a CBD only or high CBD cannabis treatment during the day to avoid impairment and then a THC/CBD treatment at night to support sleep – these are likely to be in an oil format. The effects of cannabis oils typically last longer than flower, about 6–8 hours.

Inhaled cannabis formats (dried herb, oil cartridges, metered dose inhalers): May also be prescribed for acute anxiety (such as panic attacks) due to rapid onset of effects. For patients who are sensitive to THC, a high dose CBD in may be prescribed. The effects of inhaled formats typically last shorter than oils, about 1–2 hours.

Exploring medicinal cannabis as a treatment option for anxiety with your patients 

While cannabis is not a first-line treatment in Australia, it is also not a last resort. Meaning your patients do not need to have exhausted all of their treatment options to be eligible for medicinal cannabis access. 

Mental health conditions like anxiety can be complex diagnostically and therapeutically. Alongside an effective treatment plan and medications, referring your patient to a psychiatrist or psychologist can be extremely helpful for identifying the underlying source of the anxiety, and assisting in treating your patient holistically.   

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