King's College London

New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London, in partnership with the South London and Maudsley NHS Foundation Trust (the Trust) and Maudsley Charity, has found that the NHS Cannabis Clinic for Psychosis (CCP) offers a feasible and effective treatment strategy to help young adult cannabis users to significantly cut down and even stop their cannabis use.

The research, published in the BJPsych Open, is a proof-of-concept analyses of the data from the first 46 patients who completed the intervention offered by the only clinic of its kind in the UK, and suggests that it could be used as a blueprint for other clinics elsewhere.

At the time of their referral, 93per cent (43) of participants were using high potency cannabis, and 91 per cent (42) were using cannabis daily.

Participants were given weekly one-on-one consultations with a mental health professional and access to an online weekly peer support group. Following the intervention, researchers found that 74 per cent (34) of participants completely stop using cannabis, while 26 per cent (12) reduced the frequency and potency of their cannabis use.

Participants also reported reductions in their feelings of paranoia, delusion, anxiety and depression, as well as a remarkable improvement in their levels of day-to-day functioning, such as returning to studying or work.

Professor Marta Di Forti, the study’s first author and the clinic’s lead clinician from the Trust said, “There is an assumption that cannabis is largely safe. The young people I see in my clinic represent a minority that are using cannabis in a harmful way to the point where it is impacting their ability to manage day to day life as a result of developing clinical psychosis with disabling paranoia and intrusive delusional thoughts.

“This study shows that, with the right kind of help, which uses a flexible and personalised model of care that combines expertise in managing psychosis and addiction, young adults with a psychotic disorder can be supported to decrease the regularity and potency of their cannabis use with clinically relevant drops in levels of paranoia, delusion, depression and anxiety – conditions that can all get in the way of someone thriving in their life.”

Heavy cannabis use is the most preventable risk factor for poor functional and clinical outcomes among patients with psychosis. Young adults with a psychotic disorder who continue to use cannabis are more likely to be readmitted to hospital, have shorter times between relapses, are more likely to be admitted Compulsorily in Psychiatric Intensive Care under Sections of the Mental Health Act, and are less likely to regain good function.

Professor Sir Robin Murray, the study’s senior author and Professor of Psychiatric Research at King’s IoPPN said, “Any substance can be considered harmful when the use of that substance affects a person’s ability to manage their day-to-day life. Most, if not all, of the participants on this study began to see an improvement in their quality of life when they cut down on the amount of cannabis that they were using. Not only did their psychotic symptoms ease, but many have since gone on to successfully apply for jobs or have mentioned that relationships have become easier to manage.”

John, a former patient of the clinic said, “Attending the clinic provided me with the emotional support I needed when I was struggling. It gave me the confidence to get out of the house. The more that I worked with the team, the more I was able to cut down on my cannabis use. I was never judged, and my key workers always had belief in me.”

Professor Di Forti concludes, “This study is a proof of concept that demonstrates people can be helped to reduce their cannabis use. We have now been awarded funding from the Maudsley Charity to conduct a more substantial trial to clarify how effective this is compared to local treatment as usual. What is clear to me, however, is how many people need help. We are turning people away from the clinic every day; both because they are outside of our catchment area, but also because we are at capacity.”

This study was possible thanks to funding from Maudsley Charity and the Medical Research Council.

 

A proof-of-concept analysis of data from the first NHS clinic for young adults with comorbid cannabis and psychotic disorders (DOI10.1192/bjo.2024.782) (Marta Di Forti, Benjamin W Bond, Edoardo Spinazzola, Giulia Trotta, Jodie Lynn, Richard Malkin, Naba Kamran Siddiqui, Sultan Demir, Titilayomi Opadokun, Perry BM Leung, Zhikun Li, Gabriella Baxter, Elizabeth Appiah-Kusi, Tom Freeman, Hannah Walsh, Tommaso Squeri, Daria Semikina, Felicity Amberson-Jones, Isabelle Austin-Zimmerman, Tim Meynen, Diego Quattrone, and Robin M Murray) was published in BJ Psych Open.  

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