Imaging Cannabinoid Receptors Using Positron Emission Tomography (PET) Scanning
United States100 participantsStarted 2010-07
Plain-language summary
The aim of the present study is to assess the availability of cannabinoid receptors (CB1R) in the human brain. CB1R are present in everyone's brain, regardless of whether or not someone has used cannabis. The investigators will image brain cannabinoid receptors using Positron Emission Tomography (PET) imaging and the radioligand OMAR, in healthy individuals and several conditions including 1) cannabis use disorders, 2) psychotic disorders, 3) prodrome of psychotic illness and 4) individuals with a family history of alcoholism, 5) Post-Traumatic Stress Disorder 6) Opioid Use Disorder using the PET imaging agent or radiotracer, \[11C\]OMAR. This will allow us to characterize the number and distribution of CB1R in these conditions. It is likely that the list of conditions will be expanded after the collection of pilot data and as new data on cannabinoids receptor function and psychiatric disorders becomes available.
Those in the cannabis us disorder arm of the study will have a PET scan on at least three occasions: once while smoking as usual, once after 48-hours of abstinence from cannabis, and a final time after 4 weeks of abstinence. Additional scans may be conducted within the 4 weeks and the last scan may be conducted well beyond 4 weeks. Similarly, while most schizophrenia patients may get scanned just once, a subgroup of patients may get scanned more than once. For example to tease out the effects of medications, unmedicated patients may get scanned while unmedicated and again after treatment with antipsychotic medications. Similarly prodromes may get scanned while in the prodromal stage off medications, on medications and after conversion to schizophrenia.
Who can participate
Age range
18 Years – 55 Years
Sex
MALE
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Males ages 18-55
* For cannabis users:
* Willing to abstain from cannabis use for four weeks
* For schizophrenia:
* Meets DSM-IV-TR criteria for schizophrenia or schizoaffective disorder
* For prodrome for psychotic illness:
* Meets SIPS criteria for prodromal syndrome
* For family history positive:
* First degree relative with alcoholism
* For Post-Traumatic Stress Disorder
* Meets DSM-IV-TR criteria for PTSD
* For OUD
* Meets DSM-IV-TR criteria for Opioid Use Disorder
Exclusion Criteria:
* Current neuro-psychiatric illness (including cannabis dependence) or severe systemic disease. Cannabis use disorder is permitted in the cannabis dependent group. Schizophrenia and schizoaffective disorder is permitted in the schizophrenia group. Psychotic symptoms are permitted in the prodromal group. Post-Traumatic Stress Disorder is permitted in the PTSD group and Opioid Use Disorder is permitted in the OUD group.
* Presence of ferromagnetic metal in the body or heart pacemaker
* Have had exposure to ionizing radiation that in combination with the study tracer would result in a cumulative exposure that exceeds recommended exposure limits
* Are claustrophobic
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.