This study will investigate whether cannabidiol (CBD), the primary centrally and peripherally active non-intoxicating compound in the cannabis plant, exerts anti-neuroinflammatory effects in patients with chronic low back pain (cLBP) with or without mild-to-moderate depression.

This is a randomized, double-blind, 2-arm mechanistic trial that seeks to assess the effects of CBD and placebo in patients with cLBP with and without mild-to-moderate depression, using integrated positron emission tomography / magnetic resonance imaging (PET/MRI) scans. The use of integrated PET/MRI will make it possible to simultaneously evaluate neuroinflammation (using [11C]PBR28, a second-generation radioligand for TSPO) and striatal function (using the Monetary Incentive Delay task, a validated fMRI task that probes behavioral and neural responses to rewards and losses).

Inclusion Criteria:

1. Age ≥ 18 and ≤ 75;
2. The ability to give written, informed consent;
3. Fluency in English;
4. Average worst daily pain of at least 4 on a 0-10 scale of pain intensity, during a typical day. Pain needs to be present for at least 50% of days during a typical week;
5. On a stable pain treatment (pharmacological or otherwise) for the previous four weeks;
6. Diagnosis of chronic low back pain, ongoing for at least 6 months prior to enrollment.
7. High or mixed affinity binding to [11C]PBR28 identified by the Ala147Thr TSPO polymorphism in the TSPO gene (rs6971)

Exclusion Criteria:

1. Outpatient surgery within 2 weeks and inpatient surgery within 1 month of the time of scanning (this timeframe may be extended if they are not fully recovered from the surgery);

2. Elevated baseline transaminase (ALT and AST) levels above 3 times the Upper Limit of Normal (ULN), accompanied by elevations in bilirubin above 2 times the ULN;

3. Any interventional pain procedures within 6 weeks prior to scanning procedure or at any point during study enrollment;

4. Surgical intervention or introduction/change in opioid regimen at any point during study enrollment;

5. Contraindications to fMRI scanning and PET scanning (including presence of a cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head or previous neurosurgery, prosthetic heart valves, claustrophobia);

6. Implanted spinal cord stimulator (SCS) for pain treatment;

7. Any history of neurological illness or major medical illness, unless clearly resolved without long-term consequences;

8. Current or past history of major psychiatric illness (PTSD, depression, and anxiety are exclusion criteria only if the conditions were so severe as to require hospitalization in the past year);

9. Harmful alcohol drinking as indicated by an AUDIT score ≥ 16;

10. Pregnancy or breast feeding;

11. History of head trauma requiring hospitalization;

12. Major cardiac event within the past 10 years;

13. Regular use of recreational drugs in the past 3 months;

14. Use of cannabis-containing products, such as products containing THC or over the-counter or dispensary CBD, for 2 weeks prior to starting the study medication and during the 4 weeks of taking the study medication;

15. Use of immunosuppressive medications, such as prednisone, TNF medications within 2 weeks of the visit;

16. Current bacterial or viral infection likely affecting the central nervous system;

17. Epilepsy;

18. Use of the medications valproate and clobazam, which may increase risk of hepatic AEs;

19. Safety concerns related to use of any of the following medications will be discussed on an individualized basis with a physician:

    • Strong and moderate CYP3A4 inhibitors including boceprevir, cobicistat, conivaptan, danoprevir, elvitegravir, ritonavir, indinavir, itraconazole, ketoconazole, lopinavir, paritaprevir and ombitasvir and/or dasabuvir, posaconazole, saquinavir and telaprevir, tipranavir, clarithromycin, diltiazem, idelalisib, nefazodone, nelfinavir, troleandomycin, voriconazole, aprepitant, cimetidine, ciprofloxacin, clotrimazole, crizotinib, cyclosporine, dronedarone, erythromycin, fluconazole, fluvoxamine, imatinib, tofisopam, disulfiram, and verapamil;
    • Strong and moderate inhibitors of CYP2C19 including fluoxetine and ticlopidine;
    • Sensitive and moderately sensitive substrates of CYP2C19 including clobazam, lansoprazole, omeprazole, S-mephenytoin, and rabeprazole;
    • Sensitive and moderately sensitive substrates of CYP1A2 including alosetron, duloxetine, ramelteon, tasimelteon, theophylline, tizanidine, pirfenidone, and ramosetron;
    • Sensitive and moderately sensitive substrates of CYP2B6 including bupropion and efavirenz;
    • Sensitive and moderately sensitive substrates of CYP2C8 including repaglinide, montelukast, pioglitazone, and rosiglitazone;
    • Sensitive and moderately sensitive substrates of CYP2C9 including tolbutamide, celecoxib, glimepiride, and warfarin;
    • Sensitive and moderately sensitive substrates of UGT1A9 including diflunisal, propofol, and fenofibrate;
    • Sensitive and moderately sensitive substrates of UGT2B7 including, gemfibrozil, lamotrigine, and morphine;

20. CNS depressants including all antipsychotics, benzodiazepines (except for alprazolam, clonazepam, and lorazepam, which have low binding affinity to TSPO44-48), and non-benzodiazepine sleep aids that have a known unsafe reaction with CBD;

21. Use of opioids ≥ 30 mg morphine equivalents on average per month;

22. Actively suicidal, history of suicide attempt or an aborted attempt within the last 5 years, or engagement in non-suicidal self-injurious behavior within the last year;

23. Allergy to sesame oil, and any other ingredients of EPIDIOLEX;

24. Any other contraindications to CBD administration noted by the study physician;

25. Any significant change in drug use and pain treatment from screening visit;

26. In the opinion of the investigators, unable to safely participate in this study and/or provide reliable data (e.g., unable to reliably rate pain; unlikely to remain still during the imaging procedures, etc).

All data, code, and materials used in the analyses can be provided by Jodi Gilman and Marco Loggia and Massachusetts General Hospital pending scientific review and a completed data use agreement/material transfer agreement beginning one year after publication of the results. Requests for all materials should be submitted to Jodi Gilman at jgilman1@mgh.harvard.edu or to Marco Loggia at marco.loggia@mgh.harvard.edu.

Data will become available beginning one year after publication of the results.

Data will be provided pending a scientific review and a completed data use agreement/material transfer agreement. Requests should be submitted to Jodi Gilman at jgilman1@mgh.harvard.edu or to Marco Loggia at marco.loggia@mgh.harvard.edu