Can cannabis help with autoimmune diseases like rheumatoid arthritis or lupus?

The evidence for cannabis in autoimmune diseases is promising but limited. For rheumatoid arthritis, a 2006 RCT of nabiximols (THC:CBD) showed significant reductions in pain and disease activity scores vs. placebo — the only RCT in RA to date. For multiple sclerosis, nabiximols is approved in multiple countries for spasticity, with robust RCT evidence. For lupus, IBD, and psoriasis, evidence is primarily observational or preclinical. The theoretical basis is strong — CB2 receptors are densely expressed on immune cells, and cannabinoids modulate the cytokine profiles implicated in autoimmune pathology. However, the immunosuppressive effects of THC raise concerns about infection risk, and CBD's clinical evidence in autoimmune conditions lags behind its preclinical promise.