Medical Cannabis and Mental Health: What Does the Data Say?

Across the UK, an estimated 1 in 4 adults experience a mental health condition each year. For many, finding the right treatment can be a long and frustrating journey. As access expands, more patients are exploring whether medical cannabis could support mental health, in particular those with anxiety, depression, or ADHD.

While it is not a cure, emerging evidence suggests that, when used under clinical supervision, cannabis-based medicines may provide meaningful support for some individuals. However, many of these findings come from real-world studies where multiple influencing factors are difficult to control, meaning it is not possible to attribute outcomes solely to medical cannabis.

Importance of Balance

Anxiety is one of the most common reasons patients explore medical cannabis for their mental health. Data from the UK Medical Cannabis Registry shows that among people prescribed cannabis-based medicines for generalised anxiety disorder (GAD), 38.3% achieved a 50% or greater reduction in anxiety symptoms at six months, while 43.6% experienced a clinically significant improvement in overall wellbeing.¹ Patients also reported better sleep and quality of life.²

CBD — the non-intoxicating compound in cannabis — appears particularly promising. One study found that CBD significantly reduced anxiety in teenagers with social anxiety disorder³. However, higher levels of THC (the psychoactive compound) can sometimes worsen symptoms; long-term, heavy THC use has been associated with increased anxiety and faster heart rate.⁴

The takeaway? Products with a balanced or CBD-dominant cannabinoid profile, prescribed at the right dose, may help reduce anxiety symptoms for some patients.

Lifting Mood and Motivation

Depression affects nearly 8 million people in the UK, and while antidepressants remain first-line treatment, they are not effective for everyone. A 2024 clinical study found that medical cannabis was well tolerated and linked to clinically meaningful improvements in mood and daily functioning.⁵ Researchers believe cannabinoids may work by influencing the brain’s endocannabinoid system, which helps regulate mood and emotional response.⁶

However, results vary. A large meta-analysis of over 300,000 participants found that long-term cannabis use was linked to a 29% higher risk of developing depressive symptoms.⁷ The most positive outcomes tend to occur with moderate, medically supervised use, not daily, high-THC consumption.

ADHD: Focus or Fog?

Around 2.6 million adults in the UK live with ADHD,⁸ and while standard medications are often effective, some patients struggle with side effects or limited benefit. In a small randomised trial, adults treated with a balanced THC:CBD spray showed modest improvements in impulsivity and emotional regulation.⁹

However, other studies have found no measurable improvement and even signs of reduced motivation and attention at higher THC doses.¹⁰ Because cannabis can affect short-term memory and concentration, any use in ADHD should be monitored carefully by a clinician experienced in cannabinoid medicine.

A Step Forward

Medical cannabis is not a one-size-fits-all treatment, but for some, it offers a valuable new option. CBD-dominant or balanced formulations appear most promising for anxiety and mood support, while research into ADHD remains early but encouraging.

With more than 100 active clinical trials worldwide investigating cannabinoids and mental health, understanding is expanding quickly. Used responsibly and under medical guidance, medical cannabis can play a supportive role — not as a cure, but as another tool to help patients regain balance and quality of life.

References

1. UK Medical Cannabis Registry (2024). Generalised anxiety disorder outcomes: case series. International Clinical Psychopharmacology.

2. Curaleaf Clinic (2024). Outcomes for generalised anxiety disorder from the UK Medical Cannabis Registry.

3. Masataka, N. (2019). Anxiolytic effects of repeated cannabidiol treatment in teenagers with social anxiety disorders. Frontiers in Psychology.

4. Hoch, E. et al. (2019). Medicinal cannabis and mental health: A systematic review. BMC Psychiatry.

5. Bendimerad, D. et al. (2024). Effectiveness of medical cannabis for the treatment of depression. Journal of Psychopharmacology.

6. Zou, S., & Kumar, U. (2018). Cannabinoid receptors and the endocannabinoid system. Frontiers in Psychiatry.

7. Kaur, R. et al. (2024). Association between cannabis use and depression: A systematic review and meta-analysis. PLoS ONE.

8. ADHD Foundation (2023). Adult ADHD prevalence in the UK.

9. Cooper, R. E. et al. (2017). Cannabinoids in ADHD: A randomized controlled trial. Medical Cannabis and Cannabinoids.

10. Amin, M. et al. (2023). Evaluation of cannabis use in patients with ADHD: A systematic review. Journal of Attention Disorders.