Case study: How the Cannabis Clinic is transforming care for people with psychosis and cannabis addiction
The Cannabis clinic has undertaken a revolutionary approach to dual diagnosis. They noticed that almost 2/3 of individuals accessing early intervention services across the Trust were using cannabis at the time of their first psychosis presentation.
Traditionally, mental health and addiction services struggled to meet the needs of individuals with psychosis and cannabis addiction. Addiction services were not designed to support people with psychosis and mental health services often lacked expertise in cannabis dependence. Furthermore, they lacked the flexibility needed to address cannabis dependence in individuals with psychosis; a population with unique challenges and barriers to engaging with services, including developing trust and symptoms interfering with engagement.
This meant that many individuals fell through the cracks – caught in between systems that weren’t built to accommodate their dual diagnosis. Recognising this critical gap, the team launched the cannabis clinic.
What were the project aims?
The project set out to bridge this gap. They adopted the learnings from a major clinical trial which tested an intervention for cannabis use disorder with people with psychosis. The trial was unsuccessful because it was too rigid. It failed to account for the fact that there needs to be a very important individual and personalised component to this kind of intervention
Therefore, rather than forcing patients into a fixed, one size fits all addiction programme, the cannabis clinic decided to implement a bespoke, flexible and highly person-centred approach.
How was it done?
The clinic’s philosophy is to meet people where they are, not where clinicians expected them to be. They collaborate with the people they care for - asking them what they need rather than being prescriptive.
They also use an individualised care plan, adopting a different combination of interventions and tools, adjusted to the needs of the individual.
Also, in recognition of the fact that different people progress at their own pace, service users are not required to use the full 20 sessions, neither are they turned away from the service if they haven’t met their goals within that time. Furthermore, if they need extra time, due to being readmitted to hospital, or needing to prioritise other work or treatment, such as trauma work, the service remains flexible, allowing them to take the time they need or pause their sessions as necessary.
Additionally, they put no pressure on service users to quit immediately. As long as they had a willingness to engage, or even a tiny spark of curiosity about how cannabis affects them, this was enough for the team to get started. This approach makes it easier for individuals to explore change at their own pace.
One of the clinic’s biggest successes has been its online peer group, where people can listen, talk and learn in a safe, non-judgmental space. Held weekly and attended by an average of 30 people each session, the group gives participants a chance to hear from world-leading experts about cannabis, psychosis and addiction. The sessions are interactive. As well as this, as the sessions take place online, even patients on hospital wards can join in, removing barriers to access.
The team also recognised that families also need help supporting relatives with cannabis use and psychosis. Therefore, in August 2024 they launched a carer’s group, bringing together families from the UK and even the United States. The group collaborates with Johnny’s Ambassadors, a US-based charity started by a mother who lost her son to cannabis-associated psychosis. This cross-border connection has been deeply moving, as families share experiences, challenges and support.
For those who prefer in-person support, a breakfast club was established, enabling people to find connection with others going through a similar experience.
What were the results?
The clinic has seen consistently strong attendance, with its peer group not only growing in numbers but also fostering deep engagement - so much so that participants express eagerness to return even when sessions pause for a summer break. Beyond attendance, the programme has made a tangible impact, improving outcomes in treating cannabis dependence and psychosis. (data can be inserted here). Service users benefit not just from expert-led support but also from a growing library of invaluable resources, including educational content, powerful lived experience testimonies, self-assessment tools and therapeutic tools.
In early 2024, the Cannabis Clinic published a landmark proof-of-concept study examining outcomes from the first 46 individuals to complete their intervention. The results were striking. 74% of participants achieved full abstinence from cannabis, while the remainder significantly reduced their use. Beyond cannabis reduction, the study showed broad improvements in clinical symptoms, including delusions, paranoia, depression and anxiety. Remarkably, just 8.7% of participants were in work or education at the start of the intervention. By the end, this number had jumped to over 90%. These findings provide robust early evidence that the clinic’s flexible, person-centred model is not only feasible, but highly effective in supporting recovery in young adults with both psychosis and cannabis addiction.
What’s next?
With demand rising, the team needs more resources to accommodate more patients and reduce waiting times. For this group, being on a waiting list means potentially missing the chance of working with them when they feel motivated to engage. They also require more research and funding. Securing long-term resources is critical.
As well as this, the team would like to see replication in other NHS Trusts. The clinic’s success shows that rigid, traditional addiction models do not work for people with psychosis. By sharing its approach, the team hopes to see similar clinics established nationwide. They also hope for this clinic to be used as a case study for medical training, ensuring mental health professionals and students understand the complexities of dual diagnosis and its care.
For too long, cannabis use and psychosis have been treated separately, leaving many patients without the right support. This clinic is redefining the standard of care – blending mental health and addiction care into a service that is truly person-centred. In doing so, it is transforming lives, offering hope and filling a long-overlooked gap in the healthcare system. Hopefully, with the right resources and raising awareness of the service’s success, this can be replicated on a nation-wide scale.
