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.
Between 21-65 years old
Currently 30 days cannabis free
Lower back pain for three months or more
Are not taking opioids
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.
Parallel
Active Cannabis
Drug400 mg of vaporized and inhaled active cannabis (5.1%)
Placebo Cannabis
Drug400 mg of vaporized and inhaled placebo cannabis (\<.1%)
Cerebral Blood Flow (CBF)
Changes in brain blood flow and oxygen levels will be measured using non-invasive MRI-based brain imaging methods. These scans will assess how much blood is reaching brain tissue and how oxygen levels in the brain change over time.
Pain Ratings
Pain ratings will be assessed in response to noxious heat stimulation. Pain intensity and pain unpleasantness will be measured using a 0-10 Visual Analog Scale (VAS), where 0 indicates "no pain" and 10 indicates "most intense imaginable pain" or "most unpleasant imaginable pain." Higher scores indicate greater pain intensity or unpleasantness. Subjective response to cannabis will be assessed using a 0-10 Numeric Rating Scale (NRS), with higher scores indicating greater subjective effects.
Neurochemical Metabolites
We will use a specialized, non-invasive brain scan called proton magnetic resonance spectroscopy (1H-MRS) to measure certain brain chemicals linked to pain processing, including glutamate, GABA, and myo-inositol. The scan uses radiofrequency signals (sim
Respiration Rate
Changes in breathing rate may be associated with pain relief and improved well-being. Breathing rate will be monitored continuously in real time to ensure accurate data collection.
THC Concentrations
THC concentrations will be measured to evaluate the relationship between THC levels and pain relief.
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