People keep talking about ketamine. The drug has become a favorite of celebrities, billionaires, and ordinary patients, many of whom view it as a potential miracle drug for depression and other mental health conditions. Whether on Facebook or Instagram, patients and clinics alike are giddy about the possibilities. But it is a drug that can be abused and can be deadly. Thus, ketamine is the latest challenge for Meta, the social media platforms’ parent company, which for years has struggled to moderate posts and ads touting health-related products like weight loss supplements and dodgy covid-19 …