Schizophrenia is a mental health condition which results in an altered perception of everyday life. It is commonly associated with such ‘psychotic’ symptoms as seeing, hearing, or believing things that aren’t the reality for other people. Although high-concentration THC is known to worsen such symptoms, evidence suggests that this isn’t true of balanced THC/CBD. This may be because the CBD counteracts the psychosis-inducing effects of THC, through the raising of anandamide levels. There’s also some evidence that CBD resolves the brain disconnection effects of schizophrenia.


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Condition overview

Schizophrenia is a chronic mental health condition which affects people’s thoughts, feelings, and behaviours. It is associated with a distorted perception of reality, likely to be highly concerning for the individual, as well as their friends and family. Around 1 in every 100 people suffer from this condition at some point during their lives, with onset typically occurring among men in their early to mid-20s and women in their late 20s. There is a relatively low risk among children and those aged over 45.

Common symptoms

There are a range of behaviours associated with schizophrenia. The condition may develop at different rates and with different levels of severity.

Symptoms of schizophrenia include:

  • Anxiety
  • Delusions
  • Hallucinations
  • Avoidance
  • Disorganised thinking
  • Abnormal motor behaviour
  • Depression
  • Sleep loss

Common causes

It is not known what causes schizophrenia, but researchers believe that a combination of genetics, brain chemistry and environment is likely to contribute to the development of the disorder. It is thought that some people are at particular risk and that the condition may be triggered by impactful life events.

Clinical studies have shown that schizophrenics tend to have a neurotransmitter imbalance, particularly in the levels of dopamine and glutamate. There is an apparent difference in the brain structure and central nervous system of those with the condition.

Potential causes of schizophrenia include:

  1. Personal abuse and harassment
  2. Loneliness and isolation
  3. Genetic inheritance (schizophrenia tends to run in families)
  4. Recreational drug use
  5. Pregnancy and birth complications

Standard treatment

Medications are the cornerstone of schizophrenia treatment, with antipsychotics (e.g aripiprazole) being the most commonly prescribed drugs. Antipsychotics are thought to control symptoms by affecting the brain neurotransmitter dopamine. However, medications for schizophrenia can cause significant side effects, so patients can sometimes be reluctant to take them. 

Once psychosis recedes, in addition to continuing on medication, psychological interventions are important and these include individual psychotherapy and social skills training. 

Electroconvulsive therapy (ECT) may also be considered in adults who do not respond to drug therapy.

How medical cannabis could help

The psychoactive effects of THC may mimic the presentation of psychotic symptoms, including paranoia, sensory alteration, euphoria, and hallucinations. THC is therefore contraindicated in patients with schizophrenia.

CBD, however, is known to counteract these psychoactive effects of THC, so research into its usefulness in schizophrenia is currently ongoing. Several randomised controlled trials have found that high doses of CBD can improve symptoms in patients with schizophrenia. In one study, CBD demonstrated equivalent efficacy to the antipsychotic amisulpride, with fewer side effects. CBD has also been found to partially normalise aberrant activity in brain areas associated with increased psychosis risk, suggesting it could confer some protective effects in young people at high risk of developing schizophrenia.

FAQs about Medical Cannabis

FAQs about Medical Cannabis FAQs about Medical Cannabis
Is medical cannabis legal in the UK?

Yes. Cannabis-based medicinal products (CBMPs) have been legal since the 1st of November 2018, when they moved from a Schedule 1 product to a Schedule 2 product. This reflects their potential for medical use.

Who is allowed to prescribe medical cannabis in the UK?

Cannabis-based medicinal products, also known as CBMPs, can be prescribed by private consultants, when appropriate, within their specialty area when there is unmet clinical need.

In the UK cannabis medicines are accessed primarily via private clinics. However, any specialist physician can prescribe cannabis medicines. GROW® is here to provide education and support to any specialists looking to prescribe or just to find out more.

Is medical cannabis available on the NHS?

There are 3 licensed medicines which contain cannabinoids – Epidiolex for some forms of epilepsy, Sativex for multiple sclerosis (MS), and Nabilone for chemotherapy-induced nausea and vomiting (CINV). However, only a handful of prescriptions have been issued in the NHS to date.

Most cannabis-based medicinal products (CBMPs) are instead unlicensed, and they must be written on a private prescription, typically issued by private clinics specialising in medical cannabis treatment.

What cannabis medicines are available?

Cannabis medicines come in multiple forms; flowers, often referred to as herbal cannabis (to be vaporised, rather than smoked), oils (taken under the tongue) and capsules. Cannabis medicines come in high-THC, high-CBD and balanced varieties.

Smoking medical cannabis is illegal. Medical cannabis can instead be taken in different forms depending on the desired speed of onset and duration of action, which is discussed between the patient and their doctor.

Which clinic should I use?

It’s important to find a clinic that works for you. Most importantly you need to find a Doctor that specialises in your condition. For example, patients with pain will need to see pain specialist, while those with a mental health condition must see a psychiatrist.

Which pharmacies can I use?

It’s important for patients to know they can use any pharmacy that supplies the appropriate medicines in the UK.

Some clinics have a preferred pharmacy but will be able to send prescriptions to others if needed. If patients have any questions about available medicines, they can contact IPS Pharma.

What should I do before my consultation?

To speed up the process, patients should bring a copy of their medical records. These are then forwarded to the clinic in advance of the first consultation.

Is medical cannabis the same as over-the-counter CBD?

No. Cannabis-based medicinal products (CBMPs) are only prescribed by GMC-registered specialist doctors. As they are medicinal, CBMPs are regulated by the Medicines and Healthcare products Regulatory Agency (MHRA); which ensures the safety, quality, and effectiveness of medicines in the UK.

Over-the-counter (OTC) CBD products can be purchased without a prescription in pharmacies, health food shops, or online. These may come in forms such as oil tinctures, capsules, or vapes. They are not medicinal products as they are regulated by the Food Standards Agency (FSA) as a food supplement, with a 0.3% limit on THC.

What if I don’t get a prescription?

Patients are free to seek a second opinion from another clinic. Patients should ensure the clinic has communicated their reasons for deciding not to prescribe. It may be that they feel you should try other medicines before trying cannabis medicines, or that they need to see more information about your medical history before they are happy to prescribe.

How can I learn more about medical cannabis?

For patient enquiries - [email protected]

For doctor enquiries - [email protected]

For all other enquiries – [email protected]

Healthcare professionals can also sign up to our Doctor Portal.

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