NCT04982965 · University of California, San Diego
Brain Mechanisms Supporting Cannabis-induced Pain Relief
What this study is about
Chronic low back pain is a common and disabling condition that affects millions of people in the United States. Many people with chronic low back pain do not get enough relief from current treatments. Cannabis may help reduce pain, but researchers do not fully understand how it affects the brain in people with chronic pain.
View original scientific description
Chronic low back pain is a common and disabling condition that affects millions of people in the United States. Many people with chronic low back pain do not get enough relief from current treatments. Cannabis may help reduce pain, but researchers do not fully understand how it affects the brain in people with chronic pain. The purpose of this study is to examine how inhaled cannabis changes brain activity and reduces pain in people with chronic low back pain. Results from this study may help researchers better understand how cannabis works for pain and support the development of improved pain treatments.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Between 21-65 years old
- Currently 30 days cannabis free
- Lower back pain for three months or more
- Are not taking opioids
- If female and of a child bearing potential age, are not pregnant or nursing mothers
- Do not have mental or neurological conditions inhibiting sensory/motor functions
- Do not have a lifetime history of dependence on cannabis
- Do not have a lifetime history of DSM-IV schizophrenia, bipolar disorder, panic disorder, or psychosis
- Prior THC-containing cannabis experience within the past two years
- Agrees not to use cannabis outside of the study during participation in the study
- Agrees not to use opioids or barbiturates during participation in the study
- Agrees not to drive a motor vehicle within 4 hours following last use of inhaled cannabis during participation in the study
Exclusion criteria
- Active pulmonary disease
- Allergy or past adverse effects or negative past experiences from cannabis
- Positive urine drug test for THC, barbiturates, opioids, oxycodone, or methadone
- Any significant illness, including cardiovascular disease, diabetes, renal and liver disease.
- Any current or history of an immunocompromising disease or condition (such as lupus, psoriasis, multiple sclerosis, etc.)
- Any current or history of neurologic conditions, including Parkinson disease, dementia, cognitive impairment, history of seizure disorder, and history of traumatic brain injury/head injury
- Any current major psychiatric illness, such as bipolar disorder, major depression, psychosis, substance use disorder, or schizophrenia
- Any current or history of suicidal ideation or attempt
- Overt sensitivity to thermal stimulation
- Resting blood pressure \> 140/90
- Resting heart rate \> 100 beats/minute
- Institutionalized
- Claustrophobia
- MRI contraindications
- Participation in any new (within 2 weeks prior or any time after enrollment) pain management procedures during the study period
- Known history of vasovagal fainting, syncope, or severe adverse reactions associated with blood draws or needle procedures
Where
- La Jolla, California
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 3, 2026 · Source of record for eligibility and locations