Montana narcotics expert witnesses evaluate controlled-substance prescribing, diversion risks, and drug identification across clinical and forensic settings. They often come from pain medicine, addiction psychiatry, emergency medicine, pharmacy, toxicology, and law enforcement labs. In Montana, their work reflects opioid stewardship in rural critical-access hospitals and referral patterns to Billings and Missoula. They commonly assess overdose causation, standard of care, impairment, and chain-of-custody reliability.