Which types of pain respond best to cannabis?

Cannabis does not work equally well for all pain types — the evidence strongly favors certain categories. Neuropathic pain: strongest evidence. Multiple RCTs show cannabinoids effective for HIV-associated neuropathy, diabetic neuropathy, and central neuropathic pain (MS). A 2015 Cochrane review found moderate-quality evidence for cannabinoids in neuropathic pain. Mechanism: CB1 receptors in the dorsal horn and peripheral sensory neurons modulate nociceptive transmission. Inflammatory pain: moderate evidence. Cannabinoids reduce prostaglandin synthesis and inflammatory cytokines. Spasticity-related pain: strong evidence (MS, spinal cord injury). Cancer pain: moderate evidence, particularly for breakthrough pain refractory to opioids. Acute nociceptive pain (post-surgical, trauma): weakest evidence — cannabinoids appear less effective for acute nociceptive pain than for chronic neuropathic pain. Headache/migraine: emerging evidence; observational studies positive but RCTs lacking. The clinical implication: cannabis is most likely to benefit patients with neuropathic or central sensitization pain who have not responded adequately to conventional treatments.