The anaesthetic ketamine has been a popular party drug for decades due to its ability to put users in a blissful mood. Earlier this month, the American Psychiatric Association released a consensus statement acknowledging that the drug might also be a breakthrough treatment for severe depression.

The statement authors write that seven studies–all placebo-controlled, double-blind, and randomized–provide evidence that ketamine therapy is a "rapid and robust, albeit transient" response to severe clinical depression. The treatment is effective within hours, while conventional antidepressants generally take weeks to work. The transient nature of the drug, meanwhile, suggest it works best with twice-weekly dosing.

Ketamine hasn't been approved for treating depression, but Yale psychiatrist Gerard Sanacora succinctly explained to NPR why the drug's off-label status hasn't deterred him:

Sanacora says other doctors sometimes ask him, "How can you be offering this to patients based on the limited amount of information that's out there and not knowing the potential long-term risk?" Sanacora has a simple answer. "If you have patients that are likely to seriously injure themselves or kill themselves within a short period of time, and they've tried the standard treatments, how do you not offer this treatment?"

It certainly seems that the long-term risks of ketamine therapy, regardless of how severe they may be, are preferable to the short-term risk of a successful suicide attempt.

The APA paper closes with the hunch that "economic factors make it unlikely that large-scale, pivotal phase 3 clinical trials of racemic ketamine will ever be completed," which means patients with treatment-resistant depression who'd like to give ketamine a shot will need an appointment at one of a handful of clinics offering ketamine treatment. Or, they can apply for enrollment in a philanthropic or federally funded ketamine study, of which there don't appear to be many.

This is a rather strange fate for a drug that the APA says has "generated much excitement and hope for patients with refractory mood disorders and the clinicians who treat them," but it's also an indictment of the Food and Drug Administration's regulatory process. Ketamine is off patent, which means no pharmaceutical company is going to spend several million dollars per phase to get approval for a drug formulation that any company could turn around and sell, no matter how many lives it might save.