Where is it written that titles are always identical to conclusions (or lack thereof)? "In the years after the legalization of medical marijuana, states that did so had a rate that was 25% lower than what wed expect to see in that state, given past trends and what was going on in the rest of the country" is a conclusion, while not being a practical title (nor a proof of cause and effect).
I don’t think JAMA wanted to even remotely appear to endorse this so-called “conclusion” statement. I don’t blame them. Anyway the “conclusion” is misleading since “rates of opioid overdose deaths have increased in all states”.