Testing the Efficacy of the Cannabis Clinic for Patients With Psychosis (CCP) Intervention for Cannabis Use Reduction/Cessation in Patients With First Episode Psychosis (FEP)

NCT07245212 | Not Yet Recruiting DMC

• 1 other identifier: 361577
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

Brief Summary

People suffering from psychosis who use cannabis experience more relapses, long and compulsory admissions, with huge costs to the individual, families and health services. The Cannabis Clinic for Psychosis (CCP) was developed to respond to this clinical need. A published review of the CCP's intervention showed its safety and efficacy in supporting people suffering from psychosis with reducing their cannabis use. Nevertheless, for the CCP model of care to be applied widely and benefit a larger clinical population, its intervention needs to be tested in a Randomised Control Trial (RCT). The proposed CCP RCT is a waiting list randomised controlled trial that aims to evaluate the clinical efficacy of the existing CCP intervention. Participants will be adults currently under the care of South London and Maudsley (SLaM) Early Intervention Teams for first onset psychosis, who are dependent on cannabis and who express an intention to reduce or stop their use. The RCT primary outcome will measure changes in all participants' cannabis use. Participants will be randomised to either the intervention group or the waiting list control group receiving Treatment As Usual (TAU). The CCP intervention comprises 12 weekly (+/- 4 weeks) one-to-one sessions, with optional participation in a weekly online peer group. Sessions are delivered by trained clinicians and include evidence-based psychosocial techniques, including Motivational Interviewing (MI), Cognitive Behavioural Therapy (CBT), SMART goal settings and support for co-occurring tobacco use. The treatment is non-pharmacological and administered via participant-led approach that accommodates online or face-to-face sessions to meet the patient preference. Qualitative data from the recent CCP proof of concept paper indicate that the flexibility in allowing patients choice on the session's modality (online/face to face, hybrid) increased and maintained engagement. The study is fully funded by the Maudsley Charity and due to last 30 months from the start of recruitment.

Conditions

Psychosis; Cannabis Use Disorder; First Episode Psychosis (FEP)

Keywords

Cannabis Use Disorder; Psychosis; First Episode Psychosis; Cannabis Cessation; Cannabis; Reduction; Cessation; Psychosocial Intervention; Psychosocial; Intervention; Cognitive Behavioural Therapy; Motivational Interviewing; Randomised Controlled Trial; Early Intervention in Psychosis; Cannabis Clinic for Psychosis; psychoeducation; peer support; flexibility; personalised

Outcome Measures

Primary Outcomes (1)

• Cannabis Use Disorders Identification Test-Revised score (CUDIT-R)

  The CUDIT-R is an 8-item self-report tool used to screen for cannabis use and cannabis use disorder. Items assess frequency and dependence. Scores range from 0-32, with higher scores indicating greater risk.

  Measured at a baseline assessment and 16 weeks post-randomisation.

Secondary Outcomes (14)

• Revised Cannabis Experience Questionnaire (CEQ-mv) combined with the Enhanced cannabis timeline follow back (EC-TLFB)

  Measured at a baseline assessment and 16 weeks post-randomisation.

• Psychotic Symptom Rating Scales Delusions Subscale (PSYRATS DEL)

  Measured at a baseline assessment and 16 weeks post-randomisation.

• State Social Paranoia Scale (SSPS)

  Measured at a baseline assessment and 16 weeks post-randomisation.

• Patient Health Questionnaire-9 (PHQ-9)

  Measured at a baseline assessment and 16 weeks post-randomisation.

• Generalized Anxiety Disorder-7 (GAD-7)

  Measured at a baseline assessment and 16 weeks post-randomisation.

Other Outcomes (2)

• Biological outcome

  Measured at a baseline assessment and 16 weeks post-randomisation.

• Blood Medication levels : optional

  Measured at a baseline assessment and 16 weeks post-randomisation.

Study Arms (2)

Cannabis for Psychosis Intervention + Treatment as Usual

EXPERIMENTAL

The CCP intervention consists of two main components: 1. one-to-one weekly sessions: offered both face to face and online to meet the patient preference. Patients can change the meeting modality at any point to suit their needs (e.g. transport difficulties, family commitments, or mental state). The CCP intervention uses a combination of evidence-based psychosocial interventions (PSIs) tailored to each patient's needs. Patients are offered on average 12 (SD 4.2) weeks sessions, for a maximum of 60 minutes 2. an online PEER group is facilitated by a senior member of CCP staff and moderated by two PEER mentors with lived experience of psychosis and cannabis use.

Other: CCP Intervention

Treatment as Usual / Waiting List

NO INTERVENTION

Participants continue Treatment as Usual from their clinical team while on a 16-week waiting list for the CCP intervention.

Interventions

CCP Intervention OTHER

1. one-to-one weekly sessions: offered both face to face and online to meet the patient preference. Patients can change the meeting modality at any point to suit their needs (e.g. transport difficulties, family commitments, or mental state). The CCP intervention uses a combination of evidence-based psychosocial interventions (PSIs) tailored to each patient's needs. Patients are offered on average 12 (SD 4.2) weeks sessions, for a maximum of 60 minutes. 2. an online PEER group is facilitated by a senior member of CCP staff and moderated by two PEER mentors with lived experience of psychosis and cannabis use.

Also known as: psychosocial intervention, motivational interviewing, cognitive behavioral therapy

Cannabis for Psychosis Intervention + Treatment as Usual

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• First episode psychosis Community Mental Health teams receiving care under of SLaM Early Intervention for Psychosis Adult Mental Health Teams
• CUDIT≥9 (Dependent on Cannabis)
• age=18 to 65 years old ( age range of adult psychiatric services)
• Capacity to give informed consent, as assessed by clinical teams

You may not qualify if:

• Lack capacity to consent
• High levels of suicidal ideation, judged by clinical team
• ≥2 days/week frequency use of any other illicit drug
• Participation in any other current intervention trial
• In active crises and/or expressing suicidal ideations

Sponsors & Collaborators

• King's College London: lead

Study Sites (1)

Marina House

London, SE5 8RZ, United Kingdom

Location

Related Publications (4)

• Schoeler T, Monk A, Sami MB, Klamerus E, Foglia E, Brown R, Camuri G, Altamura AC, Murray R, Bhattacharyya S. Continued versus discontinued cannabis use in patients with psychosis: a systematic review and meta-analysis. Lancet Psychiatry. 2016 Mar;3(3):215-25. doi: 10.1016/S2215-0366(15)00363-6. Epub 2016 Jan 15.

  PMID: 26777297 BACKGROUND

• Patel R, Wilson R, Jackson R, Ball M, Shetty H, Broadbent M, Stewart R, McGuire P, Bhattacharyya S. Association of cannabis use with hospital admission and antipsychotic treatment failure in first episode psychosis: an observational study. BMJ Open. 2016 Mar 3;6(3):e009888. doi: 10.1136/bmjopen-2015-009888.

  PMID: 26940105 BACKGROUND

• Di Forti M, Marconi A, Carra E, Fraietta S, Trotta A, Bonomo M, Bianconi F, Gardner-Sood P, O'Connor J, Russo M, Stilo SA, Marques TR, Mondelli V, Dazzan P, Pariante C, David AS, Gaughran F, Atakan Z, Iyegbe C, Powell J, Morgan C, Lynskey M, Murray RM. Proportion of patients in south London with first-episode psychosis attributable to use of high potency cannabis: a case-control study. Lancet Psychiatry. 2015 Mar;2(3):233-8. doi: 10.1016/S2215-0366(14)00117-5. Epub 2015 Feb 25.

  PMID: 26359901 BACKGROUND

• Lin J, Puigserver P, Donovan J, Tarr P, Spiegelman BM. Peroxisome proliferator-activated receptor gamma coactivator 1beta (PGC-1beta ), a novel PGC-1-related transcription coactivator associated with host cell factor. J Biol Chem. 2002 Jan 18;277(3):1645-8. doi: 10.1074/jbc.C100631200. Epub 2001 Nov 30.

  PMID: 11733490 BACKGROUND

MeSH Terms

Conditions

Psychotic Disorders; Marijuana Abuse

Interventions

Psychosocial Intervention; Motivational Interviewing; Cognitive Behavioral Therapy

Condition Hierarchy (Ancestors)

Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders; Substance-Related Disorders; Chemically-Induced Disorders

Intervention Hierarchy (Ancestors)

Psychotherapy; Behavioral Disciplines and Activities; Directive Counseling; Counseling; Mental Health Services; Health Services; Health Care Facilities Workforce and Services; Behavior Therapy

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Waiting list single-blind RCT

Study Record Dates

• First Submitted: November 13, 2025
• First Posted: November 24, 2025
• Study Start: December 1, 2025
• Primary Completion (Estimated): November 30, 2028
• Study Completion (Estimated): November 30, 2028
• Last Updated: November 24, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)