Does this mean one shouldn't use cannabidiol and LDN together?
From that
study saying cannabidiol modulates the opioid receptors, it's not clear to me whether it increases or decreases the opioid receptor sensitivity.
Though in
this discussion on reddit.com, someone says there's lots of anecdotal evidence to suggest smoking Cannabis does potentiate opioids (makes opioid painkillers more effective for example).
So possibly cannabidiol might potentiate LDN, making it more effective. Although if you are getting strong start-up side effects from LDN, it might potentiate those too — or cannabidiol might conceivably allow you to reduce your LDN dose and still get the benefits.
Though nobody seems to know the mechanism by which LDN helps some ME/CFS patients. It could be via the opioid receptors, in which case cannabidiol may support this mechanism; but it could be from the various other things that LDN does, like increasing met-enkephalin (opioid growth factor), and blocking TLR-4.