PTSDCANPOSTNCT05162651
Effect of Extended Cannabis Abstinence on PTSD Symptoms
A study testing Contingency-management in people with PTSD and Cannabis Use, run by Centre for Addiction and Mental Health at 1 site in Canada.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 to 55 years
- Conditions the study is for
- PTSD, Cannabis Use, Cognitive Symptom
- What is being tested?
- Contingency-management
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteCanada
- Study dates
- 2 Feb 2022to 1 Sep 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Subjects aged between 18 and 55 years (from both sexes [or genders]);
- 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);
- Diagnosis of current (past 30 days) PTSD, using the CAPS-5 on screening;
- On antidepressant medication(s) for at least 1 month (to ensure safety and homogeneity as PTSD treatment of our population);
- Be able to provide written informed consent; and
- Be able to communicate in English.
Who cannot join
- diagnosed with a severe or unstable medical illness that precludes safe participation in the study as per the study physician;
- diagnosed with schizophrenia, schizoaffective disorder, or bipolar disorder or current acute psychosis or mania based on DSM-5 criteria;
- 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
- have pain interfering with normal function as reported by the 12-Item Short Form Survey (SF-12) (moderate or higher interference).
Trial locations and contacts
1 site in 1 country.
About this study
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.
- Being tested
- Contingency-management, Enhanced usual care
- Medical subject headings
- Stress Disorders, Post-Traumatic, Neurobehavioral Manifestations
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Contingency-managementBehavioural
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.
Enhanced usual careOther
Subjects will receive structured, quantitative assessments at baseline, four, eight and twelve weeks.
| Study group | Role | What they receive |
|---|---|---|
| Contingency management group | Active comparator | Randomized to receive individual motivational interviewing therapy and contingency management Receives: Behavioral: Contingency-management; Other: Enhanced usual care |
| Control group | Other | Randomized to receive individual motivational interviewing therapy alone Receives: Other: Enhanced usual care |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Week 0-4
Secondary outcomes (1)
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.
Measured: Week 0-4
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Dec 2021
- Study start2 Feb 2022
- Primary completion1 Sep 2024
- Study completion1 Sep 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for PTSDStudies of the same condition, open and under way.
- More trials run by Centre for Addiction and Mental HealthThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- Centre for Addiction and Mental Health
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05162651
- Sponsor's protocol ID
- 087-2021
- Acronym
- CANPOST
- Status last verified
- Apr 2024
- First submitted
- 6 Dec 2021
- Last updated
- 23 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Rodas JD, Sorkhou M, Kloiber S, George TP, Hassan AN. The Effects of Extended Cannabis Abstinence in Comorbid Posttraumatic Stress Disorder and Cannabis Use Disorder. J Clin Psychiatry. 2026 Feb 18;87(1):25m16099. doi: 10.4088/JCP.25m16099.
PubMed 41734366
Study at a glance
From the registry record, last updated by the sponsor on 23 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Extended Cannabis Abstinence on PTSD Symptoms
- ClinicalTrials.gov ID
- NCT05162651
- Acronym / sponsor ID
- CANPOST / 087-2021
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- Centre for Addiction and Mental HealthUniversity, hospital or other
- Study start
- 2 Feb 2022 (actual)
- Primary completion
- 1 Sep 2024 (actual)
- Study completion
- 1 Sep 2024 (actual)
- First posted
- 17 Dec 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Contingency management group | Active comparator | Behavioral: Contingency-management, Other: Enhanced usual careRandomized to receive individual motivational interviewing therapy and contingency management |
| Control group | Other | Other: Enhanced usual careRandomized to receive individual motivational interviewing therapy alone |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Subjects aged between 18 and 55 years (from both sexes [or genders]);
- 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);
- Diagnosis of current (past 30 days) PTSD, using the CAPS-5 on screening;
- On antidepressant medication(s) for at least 1 month (to ensure safety and homogeneity as PTSD treatment of our population);
- Be able to provide written informed consent; and
Key exclusion criteria (4 listed)
- diagnosed with a severe or unstable medical illness that precludes safe participation in the study as per the study physician;
- diagnosed with schizophrenia, schizoaffective disorder, or bipolar disorder or current acute psychosis or mania based on DSM-5 criteria;
- 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
- have pain interfering with normal function as reported by the 12-Item Short Form Survey (SF-12) (moderate or higher interference).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Contingency-managementIn 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. | Behavioural | Contingency management group |
| Enhanced usual careSubjects will receive structured, quantitative assessments at baseline, four, eight and twelve weeks. | Other | Contingency management group, Control group |
Primary outcome
Severity of PTSD symptoms, as measured with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at week 4
Time frame: Week 0-4
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.
1 secondary outcome
Changes in cognitive function, as measured with various Cambridge Automated Neuropsychological Test Automated Battery (CANTAB) cognitive tests
Time frame: Week 0-4
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Oct 2026.
- Derived from this study: PubMed 41734366Rodas JD, Sorkhou M, Kloiber S, George TP, Hassan AN. The Effects of Extended Cannabis Abstinence in Comorbid Posttraumatic Stress Disorder and Cannabis Use Disorder. J Clin Psychiatry. 2026 Feb 18;87(1):25m16099. doi: 10.4088/JCP.25m16099.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Contingency-management in people with PTSD and Cannabis Use, run by Centre for Addiction and Mental Health at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 23 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Severity of PTSD symptoms, as measured with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at week 4 (time frame: Week 0-4). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05162651, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Oct 2026.