Medicinal Cannabis and Mental Health: What We Know - and What We Don’t

In recent years, medicinal cannabis has gained attention as a potential therapy for a wide range of health conditions - including mental health disorders like anxiety, PTSD, and depression. But while public interest has surged, the clinical evidence remains complex and evolving.

Let’s break down what the research shows - and what still needs more study.

Where Medicinal Cannabis May Help

While cannabis is not a “cure” for any mental health condition, some patients have reported benefits, particularly when using it under medical supervision with specific formulations. Early research and clinical experience suggest possible benefits in the following areas:

Anxiety (Generalised Anxiety Disorder, Social Anxiety, etc.)
- CBD (cannabidiol) - the non-intoxicating compound in cannabis - has shown promise in reducing anxiety symptoms, especially in low to moderate doses.
- Some studies suggest it may modulate the brain’s stress response and reduce the physical symptoms of anxiety (like rapid heartbeat).
- However, high doses of THC (the psychoactive compound) can worsen anxiety for some people.
Post-Traumatic Stress Disorder (PTSD)
- Small clinical studies and patient reports have shown that cannabis may help reduce nightmares, hypervigilance, and sleep disturbance in PTSD.
- A 2021 study found that patients with PTSD who used cannabis reported a greater reduction in symptoms than those who did not - but more research is needed to confirm long-term effects and safety.
Sleep Disorders and Insomnia (Linked to Anxiety or Depression)
- Both THC and CBD may help with falling asleep and staying asleep, particularly in individuals with stress-related insomnia.
- However, prolonged use of high-THC products may disrupt natural sleep cycles over time.

Where Cannabis May Harm Mental Health

Cannabis is not risk-free, especially when used without proper supervision. In some cases, it may actually worsen symptoms or trigger mental health issues, particularly in high-risk individuals.

THC and Psychosis Risk
- THC has been strongly linked to psychosis in vulnerable individuals, especially those with:
  - A personal or family history of psychotic disorders (e.g., schizophrenia)
  - Early cannabis use in adolescence
  - High-dose, long-term cannabis use
- For these individuals, medicinal cannabis is avoided altogether.

Depression

The relationship between cannabis and depression is complicated:

Some patients report short-term relief of symptoms like low mood or fatigue.
But long-term, heavy use (especially of high-THC strains) has been associated with worsening of depressive symptoms, especially in younger users.

Anxiety (Paradoxical Effect)

While CBD may reduce anxiety, THC can cause or worsen it - especially in higher doses or when consumed in edible form (which has a delayed onset).
Some patients experience paranoia, racing thoughts, or panic after using THC-rich products.

What About CBD? The Calmer Cannabinoid

CBD is gaining popularity as a potential non-intoxicating treatment for anxiety and stress-related conditions.

Early research shows it may help with panic disorder, social anxiety, and insomnia.
It appears to work by influencing serotonin and GABA systems in the brain.
Unlike THC, CBD does not produce a “high”, and has a favourable safety profile in most studies.

Still, more high-quality, long-term clinical trials are needed to determine:

The most effective dose
The ideal duration of treatment
Long-term safety and interactions with psychiatric medications

Why Medical Supervision Matters

It’s important to work with your prescribing healthcare professional to:

Assess whether cannabis is appropriate for your condition
Choose the right formulation (e.g., high-CBD, low-THC)
Monitor for side effects and interactions
Adjust dosing based on your response

Self-medicating with recreational cannabis is never recommended and can be particularly harmful if you have a history of mental illness or are taking other medications.

Cannabis might help - but it can also harm. Knowing the difference starts with good information and medical guidance.

Speak to your doctor about whether medicinal cannabis is right for you - and always get your information from trusted medical sources, not just social media.

Our team is always here to help. You can reach our team at 1300 420 965 or at hello@dispensedirect.com.au.

Resources

Han, K, Wang, J-Y, Wang, P-Y & Peng, Y-C-H 2024, ‘Therapeutic potential of cannabidiol (CBD) in anxiety disorders: A systematic review and meta-analysis’, Psychiatry Research, vol. 339, p. 116049, viewed 6 July 2024, <https://www.sciencedirect.com/science/article/pii/S0165178124003342#:~:text=Our%20meta%2Danalysis%20provides%20further>.
Henson, JD, Vitetta, L, Quezada, M & Hall, S 2021, ‘Enhancing Endocannabinoid Control of Stress with Cannabidiol’, Journal of Clinical Medicine, vol. 10, no. 24, p. 5852, viewed 3 January 2022, <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8704602/>.
Vaddiparti, K, Liu, Y, Bottari, S, Crump Boullosa, C, Zhou, Z, Wang, Y, Williamson, J & Cook, R 2023, ‘Improved Post-Traumatic Stress Disorder Symptoms and Related Sleep Disturbances after Initiation of Medical Marijuana Use: Evidence from a Prospective Single Arm Pilot Study ’, Medicinal Cannabis and Cannabinoids, vol. 6, no. 1, pp. 160–169.
Rehman, Y, Saini, A, Huang, S, Sood, E, Gill, R & Yanikomeroglu, S 2021, ‘Cannabis in the management of PTSD: a systematic review’, AIMS Neuroscience, vol. 8, no. 3, pp. 414–434.
Lavender, I, Garden, G, Grunstein, RR, Yee, BJ & Hoyos, CM 2024, ‘Using Cannabis and CBD to Sleep: An Updated Review’, Current Psychiatry Reports, vol. 26, Springer Science+Business Media.
Babson, KA, Sottile, J & Morabito, D 2017, ‘Cannabis, Cannabinoids, and Sleep: a Review of the Literature’, Current Psychiatry Reports, vol. 19, no. 4.
Lev-Ran, S, Roerecke, M, Le Foll, B, George, TP, McKenzie, K & Rehm, J 2014, ‘The association between cannabis use and depression: A systematic review and meta-analysis of longitudinal studies’, Psychological Medicine, vol. 44, no. 4, pp. 797–810.
Shannon , S, Lewis, N, Lee, H & Hughes, S 2019, ‘The Permanente Journal’, Europepmc.org, vol. 23, pp. 18–41.