Ketamine is a hallucinogen that has been used as an anesthetic for decades. It is also used illegally as a party drug. The drug is shown to work for treatment-resistant depression in some people.

Recently, a new industry has emerged: ketamine clinics, where patients can go on "trips" by receiving the drug as either an infusion or an injection to address a wide variety of mental health problems. But some doctors worry that it's an unregulated industry ripe for danger.