Medical Cannabis and Mental Health: Anxiety, PTSD, and Beyond

Anxiety disorders are the most common mental health conditions in the UK, affecting around 8 million people at any one time. PTSD affects approximately 4% of the population, with higher rates among veterans, emergency service workers, and survivors of trauma.

Conventional treatments — including SSRIs, SNRIs, benzodiazepines, and psychotherapy — are effective for many patients. However, a significant minority do not respond adequately, and some experience intolerable side effects. It is for this group that cannabis-based medicinal products (CBMPs) have attracted growing clinical interest.

CBD (cannabidiol) has been the most extensively studied cannabinoid for anxiety. Unlike THC, CBD does not produce psychoactive effects and does not typically worsen anxiety. Its anxiolytic (anti-anxiety) effects are thought to be mediated through multiple mechanisms, including:

• Modulation of serotonin receptors (5-HT1A) — the same receptors targeted by SSRIs
• Reduction of activity in the amygdala — the brain's fear centre
• Enhancement of endocannabinoid signalling, which regulates stress responses

A landmark 2019 study published in The Permanente Journal found that CBD reduced anxiety scores in 79.2% of patients within the first month of treatment.

PTSD is arguably the mental health condition with the strongest evidence base for CBMP treatment. The core symptoms of PTSD — intrusive memories, hyperarousal, nightmares, and emotional numbing — appear to respond particularly well to cannabinoid treatment.

Key findings include:

• A 2018 study in the Journal of Alternative and Complementary Medicine found that PTSD symptom severity decreased by 75% during periods of cannabis use compared to periods without.

• The UK Medical Cannabis Registry has reported PTSD as one of the conditions with the most consistent and significant patient-reported improvements.

• THC appears to be particularly effective at reducing nightmare frequency in PTSD — a symptom that is notoriously difficult to treat with conventional medications.

While CBD is generally anxiolytic, THC can have the opposite effect — particularly at higher doses or in individuals who are THC-naive. Acute THC intoxication can cause anxiety, paranoia, and panic attacks in some people.

This is why CBMPs for anxiety and PTSD are typically CBD-dominant preparations, with THC present only in small amounts (if at all). Your prescribing clinician will carefully titrate your dose to minimise the risk of THC-induced anxiety while maximising therapeutic benefit.

Patients with a personal or family history of psychosis are generally not considered suitable for high-THC CBMPs, and this will be assessed during your initial consultation.

The evidence for CBMPs in depression is less robust than for anxiety and PTSD. Some patients report improvements in mood and motivation, and the indirect effects of better sleep and reduced pain may contribute to improved mood.

However, there is also evidence that heavy, long-term cannabis use is associated with increased risk of depression — particularly in adolescents and young adults. Under medical supervision with appropriate dosing, this risk is managed, but it is an important consideration.

CBMPs are not currently considered a first-line treatment for depression in the UK, and most clinicians would only consider prescribing them for depression where multiple conventional treatments have failed.

If you have an anxiety disorder or PTSD that has not responded adequately to conventional treatments, you may be eligible for CBMP treatment. The process involves registering as a patient, attending a consultation with a specialist clinician, and — if appropriate — receiving a private prescription.

MEDCANN Pharmacy works with specialist clinicians who have extensive experience in prescribing CBMPs for mental health conditions. Register as a patient today to begin your assessment.