Effect of Extended Cannabis Abstinence on PTSD Symptoms (CANPOST)

This will be a 12-week randomized trial. Outpatients and patients from the Mood and Anxiety program at the Centre for Addiction and Mental Health (CAMH) with a current diagnosis of post-traumatic stressed disorder (PTSD) and cannabis-use disorder (CUD) will be randomized to receive individual motivational interviewing therapy and contingency management (n = 12) or individual motivational interviewing therapy alone (control group, n = 12) after enrolment.

Study Overview

• Status: Recruiting
• Conditions: PTSD; Cannabis Use; Cognitive Symptom; Comorbidities and Coexisting Conditions
• Intervention / Treatment: Behavioral: Contingency-management; Other: Enhanced usual care

• Study Type: Interventional
• Enrollment (Estimated): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5S 2S1
      • Recruiting
      • Centre for Addiction and Mental Health
      • Contact: Ahmed Hassan, MD, MPH; Phone Number: 34051 416-535-8501; Email: ahmed.hassan@camh.ca
      • Contact: Abigail Amartey, MPH; Phone Number: 33651 416-535-8501; Email: abigail.amartey@camh.ca
      • Principal Investigator: Ahmed Hassan, MD, MPH

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Subjects aged between 18 and 55 years (from both sexes [or genders]);
2. Diagnosed with CUD (moderate or severe) according to the Structured Clinical Interview for DSM-IV (SCID) (mode of cannabis consumption can be inhalation or ingestion);
3. Diagnosis of current (past 30 days) PTSD, using the CAPS-5 on screening;
4. On antidepressant medication(s) for at least 1 month (to ensure safety and homogeneity as PTSD treatment of our population);
5. Be able to provide written informed consent; and
6. Be able to communicate in English.

Exclusion Criteria:

1. diagnosed with a severe or unstable medical illness that precludes safe participation in the study as per the study physician;
2. diagnosed with schizophrenia, schizoaffective disorder, or bipolar disorder or current acute psychosis or mania based on DSM-5 criteria;
3. current suicidality risk as indicated by the Columbia Suicide Severity Rating Scale (C-SSRS) with concurrence after the study physician's evaluation if the response to C-SSRS questions 1 or 2 is "yes" 34; and
4. have pain interfering with normal function as reported by the 12-Item Short Form Survey (SF-12) (moderate or higher interference).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Contingency management group; Randomized to receive individual motivational interviewing therapy and contingency management	Behavioral: Contingency-management; In addition to structured assessments at baseline, four, eight and twelve months, subjects randomized to the contingency-management group will receive a contingent bonus if the participants show successful abstinence at the end of weeks 4, 8 and 12.; Other: Enhanced usual care; Subjects will receive structured, quantitative assessments at baseline, four, eight and twelve weeks.
Other: Control group; Randomized to receive individual motivational interviewing therapy alone	Other: Enhanced usual care; Subjects will receive structured, quantitative assessments at baseline, four, eight and twelve weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Severity of PTSD symptoms, as measured with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at week 4	Changes in CAPS-5 during the study phase between the group that achieved abstinence and the group that did not. In addition, we will record changes in each PTSD symptom category, which will all be part of the larger trial analysis.	Week 0-4

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in cognitive function, as measured with various Cambridge Automated Neuropsychological Test Automated Battery (CANTAB) cognitive tests	Changes between abstainers and non-abstainers on cognitive testing during the study phase.	Week 0-4

Collaborators and Investigators

• Sponsor: Centre for Addiction and Mental Health

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2022
• Primary Completion (Estimated): September 1, 2024
• Study Completion (Estimated): September 1, 2024

Study Registration Dates

• First Submitted: December 6, 2021
• First Submitted That Met QC Criteria: December 6, 2021
• First Posted (Actual): December 17, 2021

Study Record Updates

• Last Update Posted (Actual): April 23, 2024
• Last Update Submitted That Met QC Criteria: April 22, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Chemically-Induced Disorders; Nervous System Diseases; Substance-Related Disorders; Neurologic Manifestations; Marijuana Abuse; Neurobehavioral Manifestations
• Other Study ID Numbers: 087-2021

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No