Medical Cannabis for Anxiety in the UK: What the Evidence Actually Shows

Understanding what the research actually shows means looking separately at CBD, THC, prescribed cannabis products and the different types of evidence that have been collected.

 

Can medical cannabis help with anxiety?

 

Medical cannabis may help some people with anxiety, but there is not yet enough high-quality evidence to establish cannabinoids as an effective routine treatment for anxiety disorders. 

 

Some studies, particularly involving CBD, have reported improvements, while real-world data is encouraging. However, recent systematic reviews say the controlled evidence is limited.

 

Medical cannabis usually refers to unlicensed cannabis-based products for medicinal use (CBPMs). CBPMs contain varying concentrations of cannabidiol (CBD) and tetrahydrocannabinol (THC), alongside other cannabinoids and compounds. Products may be CBD-dominant, THC-dominant, or contain a balance of both, and are prescribed in different doses and formulations. All of these factors can influence their effects on symptoms like anxiety.

 

The patient populations which have been studied also vary considerably, from people with diagnosed generalised or social anxiety disorder to those experiencing anxiety alongside conditions such as PTSD or ADHD.

 

According to Dr Niraj Singh, a Consultant Psychiatrist specialising in Neurodevelopmental Psychiatry, speaking at the Cannabis Health Symposium in November 2025, the evidence base is “very mixed”. 

 

Can you get medical cannabis for anxiety in the UK? 

 

CBPMs have been legally available on prescription in the UK since November 2018. The majority of these remain unlicensed and are predominantly prescribed through private clinics. Very few prescriptions for unlicensed cannabis-based medicines are obtained through the NHS. 

 

Prescriptions can only be initiated by doctors on the General Medical Council Specialist Register when they consider it to be clinically appropriate and in the best interests of the patient.

 

Current NICE guidance for generalised anxiety disorder does not recommend medical cannabis. Established treatments include CBT and other talking therapies, and SSRIs are recommended when drug treatment is chosen, with other options considered where appropriate.

 

Eligibility for a CBPM is determined by specialist consultants on a case-by-case basis. A patient is usually required to have tried at least two other treatments for their condition without success before a CBPM will be considered. 

 

What does the clinical evidence show?

 

A major systematic review and meta-analysis published in The Lancet Psychiatry in March 2026 provides one of the most comprehensive recent assessments of cannabinoids for psychiatric conditions like anxiety. 

 

Researchers reviewed randomised controlled trials in which cannabinoids were used as the primary treatment for mental health and substance-use disorders.

 

Across the review, 54 trials involving 2,477 participants were included. Six studies concerned anxiety disorders. 

 

For anxiety specifically, four studies involving 293 participants could be combined in the meta-analysis, with the authors grading the evidence as “very low certainty”.

 

This is not the same as demonstrating conclusively that cannabinoids have no effect.

 

The review included small sample sizes, differences in populations studied, and variation in the cannabinoids being tested. CBD was the most commonly studied cannabinoid, followed by THC and combinations of the two.

 

What have CBD studies found?

 

In a double-blind study of people with social anxiety disorder, a single 600mg dose of CBD was found to reduce anxiety, cognitive impairment and discomfort during a simulated public-speaking task compared with placebo.

 

But elsewhere, in a 2022 study involving 80 participants receiving exposure therapy alongside the treatment, CBD did not improve outcomes beyond placebo.

 

Small studies have also investigated full-spectrum CBD products. An open-label phase of a Phase II trial reported reductions in anxiety among 14 participants receiving a high-CBD full-spectrum extract over four weeks. However, there was no blinded placebo group, so the results should be considered preliminary and interpreted cautiously. 

 

Is CBD or THC better for anxiety?

 

CBD and THC can have substantially different effects, so it is important to consider cannabinoid content when discussing the role of cannabis in conditions like anxiety. 

 

A 2024 study led by researchers at the University of Colorado Boulder followed 300 adults with anxiety symptoms, randomly assigned to use one of three commercially available cannabis flower products, including THC-dominant cannabis, balanced cannabis containing 12% THC and 12% CBD, or CBD-dominant cannabis.

 

Anxiety declined across the study, but CBD-dominant cannabis use was associated with lower anxiety scores than THC-dominant cannabis when researchers accounted for frequency of use.

 

However, this was a quasi-experimental study rather than a conventional placebo-controlled clinical trial. While the findings suggest CBD-dominant products may have a more favourable anxiety profile than THC-dominant products, they do not establish that CBD is an effective treatment for anxiety or that it will be preferable for every patient.

 

What does real-world evidence show?

 

Despite the lack of randomised controlled trials, real-world evidence and observational studies show that patients consistently report improvements following the use of CBPMs. 

 

One study, published in Psychopharmacology in 2023, examined 302 patients with generalised anxiety disorder enrolled in the UK Medical Cannabis Registry. Patients were prescribed cannabis oils, dried flower, or a combination. 

 

Compared with baseline, average GAD-7 scores improved by 5.3 points after one month, 5.5 points after three months and 4.5 points after six months. At six months, 43.6% of those with available data achieved at least a four-point reduction in GAD-7, while improvements in sleep and quality of life were also reported. 

 

The authors concluded that CBPMs were associated with clinically significant improvements, but called for more placebo-controlled randomised trials to examine this further.

 

RCTs vs real-world evidence

 

The gap between randomised trials and real-world evidence has become a significant point of debate within cannabis research.

 

Researchers at Drug Science recently compared RCT evidence on anxiety with outcomes from 176 patients with generalised anxiety disorder treated through Project Twenty21.

 

They reported improvements in anxiety, mood, sleep and quality of life after three months and argued that existing RCTs may not accurately represent medical cannabis treatment in clinical practice.

 

Among their criticisms are that trial populations tend to be small and may exclude patients with comorbidities or previous cannabis experience, while studies have frequently examined CBD isolates and short-term interventions rather than the varied, sustained CBMP regimens used in clinical practice.

 

However, real-world evidence has limitations of its own. Without randomisation and placebo controls, improvements may be influenced by factors including patient expectations, changes in other treatments, selection bias, and differences between people who remain in follow-up and those who do not.

 

Medical cannabis case studies 

 

Dr Singh says psychiatric patients seeking cannabis treatment frequently present with overlapping conditions and complex histories rather than anxiety existing in isolation.

 

During his presentation at Cannabis Health Symposium in November 2025, he described patients with multiple diagnoses, previous treatments and symptoms spanning anxiety, sleep, trauma and neurodevelopmental conditions.

 

PTSD and anxiety

 

One case involved a woman with a history of significant childhood trauma whom Singh considered to have complex PTSD. Her symptoms included flashbacks, intrusive thoughts, hypervigilance, secondary anxiety, insomnia and nightmares.

 

She had previously received medicines including sertraline and citalopram and had undergone private counselling. She had also used cannabis since the age of 15 and reported obtaining high-THC products through the illicit market, where consistency and composition were uncertain.

 

Following a prescription for medicinal cannabis flower, Singh reported that after one month she experienced improvements in mood and sleep alongside reductions in anxiety, flashbacks and nightmares.

 

Oils were subsequently introduced partly to reduce the amount of flower she was using, with vaporised flower increasingly reserved for breakthrough symptoms such as heightened anxiety or panic.

 

ADHD and anxiety 

 

Singh also described a 32-year-old man with adult ADHD alongside secondary anxiety and insomnia.

 

The patient had previously been prescribed stimulant medications and had used cannabis since his teens. Following treatment with medicinal cannabis oils and flower, and subsequent adjustments to the regimen, Singh reported reduced anxiety and restlessness alongside improvements in mood, attention and concentration.

 

While these case studies do not provide controlled evidence or demonstrate the efficacy of CBPMs in anxiety, they do shed light on complexities of patients presenting to clinics and how clinical practice can be applied in the real world. 

 

Singh also emphasises that cannabis-based medicines should not be viewed in isolation from wider care.

 

He added: “We should really understand what the motivations are — why is that person taking this medicine? Is it to help with sleep, anxiety, or physical pain? And what other things can be put in there to support the individual?” 

 

Can medical cannabis make anxiety worse?

 

Prescribers must be especially cautious when considering the use of THC in patients with complex mental health conditions.

 

THC can produce unwanted psychological effects, including increased anxiety, panic and paranoia. These can vary according to factors such as dose, cannabinoid composition, previous cannabis exposure and individual vulnerability. 

 

Particular caution should be applied in people vulnerable to psychotic symptoms and other serious psychiatric complications.

 

Dr Singh said: “We need to be very conscious of the THC use, particularly in vulnerable populations.”

 

A comprehensive psychiatric assessment may need to consider the underlying diagnosis, severity and stability of symptoms, other mental health conditions, previous treatment response, current medication, substance-use history and previous experiences with cannabis.

 

NICE similarly recommends that assessment of GAD considers factors including comorbid depression or other anxiety disorders, substance misuse, medical conditions, previous mental health disorders and past response to treatment.

 

Does THC affect memory?

Potential cognitive effects also need to form part of the risk-benefit discussion.

 

A 2026 randomised, double-blind, placebo-controlled study investigated the acute effects of THC across a broad range of memory functions and reported broad acute memory impairment following THC administration. However, the trial was on acute THC exposure in existing cannabis users, not medical cannabis for anxiety. 

 

So, what does the evidence actually show?

 

Real-world outcomes are encouraging, but the controlled evidence is not yet strong enough to establish medical cannabis as a routine evidence-based treatment for anxiety disorders.

 

Promising observational findings and clinician reports sit alongside a small and “uncertain” controlled evidence base, according to the 2026 Lancet Psychiatry review. 

 

Larger, longer-term trials using clearly characterised products in representative clinical populations are needed, as are high-quality observational studies capable of examining 5h4 experiences of more complex patients already receiving these medicines.

 

Continue the conversation

Mental health remains one of the most discussed and debated areas of medical cannabis practice. A dedicated session at Cannabis Health Symposium London 2026 will examine the current evidence base, while addressing concerns around safety, dependency, psychosis risk and patient selection.  Experts will discuss prescribing considerations, risk mitigation strategies and the role of cannabis-based medicines within wider mental health treatment pathways.

Book your tickets here 

 

Frequently asked questions

Can you get medical cannabis for anxiety in the UK?

It is possible for a doctor on the GMC Specialist Register to prescribe an unlicensed CBPM where they consider it clinically appropriate. However, CBPMs are not recommended by NICE as a routine treatment for generalised anxiety disorder.

Does medical cannabis work for anxiety?

Some CBD studies and UK real-world studies have reported reductions in anxiety. However, a 2026 systematic review found the controlled evidence for anxiety to be very low certainty. Medical cannabis has therefore not yet been established as an effective routine treatment for anxiety disorders.

Can THC make anxiety worse?

THC can increase anxiety, panic or paranoia in some people, although responses vary considerably. Dose, cannabinoid composition, previous cannabis exposure and psychiatric history may all affect individual responses. This is one reason clinical assessment and monitoring are particularly important when THC-containing products are prescribed for psychiatric symptoms.

Is medical cannabis safe for people with mental health conditions?

Safety depends on the individual, their diagnosis and psychiatric history, other medicines and substances, and the cannabinoid product being considered. People with complex psychiatric presentations may require particularly careful specialist assessment, risk evaluation, coordination with existing mental-health care and ongoing monitoring.