Impact of stopping cannabis use on PTSD symptoms

Effect of Extended Cannabis Abstinence on PTSD Symptoms

Not applicable Interventional Centre for Addiction and Mental Health · NCT05162651

This study is testing if stopping cannabis use can help people with PTSD feel better when they receive therapy.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment24 (estimated)
Ages18 Years to 55 Years
SexAll
SponsorCentre for Addiction and Mental Health Academic / other
Locations1 site (Toronto, Ontario)
Trial IDNCT05162651 on ClinicalTrials.gov

What this trial studies

This is a 12-week randomized trial involving outpatients from the Mood and Anxiety program at the Centre for Addiction and Mental Health. Participants diagnosed with both post-traumatic stress disorder (PTSD) and cannabis-use disorder (CUD) will be assigned to either receive individual motivational interviewing therapy combined with contingency management or motivational interviewing therapy alone. The aim is to assess the effects of extended cannabis abstinence on PTSD symptoms through these therapeutic interventions.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 55 with a current diagnosis of PTSD and moderate to severe cannabis-use disorder.

Not a fit: Patients with severe medical illnesses, certain psychiatric disorders, or acute suicidality may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved treatment strategies for individuals suffering from PTSD and cannabis-use disorder.

How similar studies have performed: While there is ongoing research into the effects of cannabis on PTSD, this specific approach combining motivational interviewing and contingency management is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
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).

Where this trial is running

Toronto, Ontario

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions PTSDCannabis UseCognitive SymptomComorbidities and Coexisting Conditions
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.