At the grand opening of a new health clinic in St. Matthews, autumn leaf-shaped cookies sit on a platter. Each has the molecular structure of ketamine painted on with icing.

Virginia Hart, with the St. Matthews Chamber of Commerce, talks about why this business is so important.

“My family suffers from depression, migraines, PTSD,” Hart says, “so what you do here is really important to my family.”

What they do here at Serenity Health is give people ketamine.

Once known as the party drug, “Special K,” ketamine is now being used to treat depression and a host of other conditions at private clinics across the country.

About a third of people seeking treatment for depression don’t respond to antidepressants. Ketamine can be effective for these people, specifically.

But there’s also scant long-term research on how safe it will be in the long-term — and depression can often be chronic.

Kit Afable is the co-founder of Serenity Health, and administers ketamine treatments there. He said patients come in six times over the course of two or three weeks for their initial treatment.

“We really did actually try to make it an environment where a patient that needs this treatment, that’s on their last leg because nothing else had worked, you know, this is something that we want to be able to provide,” Afable said.

Every session consists of an IV infusion that lasts for about an hour, and costs $375. Insurance usually doesn’t cover ketamine for mental health treatment, so patients pay out-of-pocket. After the initial six sessions, return IV infusions are $275 dollars each.

The clinic also offers a nasal spray form of the drug called Spravato, which is FDA approved for depression. It’s almost twice the cost, but it’s sometimes covered by insurance.

Ketamine has been around since the 1960s and is approved for use as anesthesia. But in 2000, Yale University published one of the first studies on ketamine in patients with depression, and found the drug might be helpful in treating them.

But to have a large body of evidence that conclusively shows ketamine works for treatment-resistant depression, a drug maker would have to run clinical trials. And there’s no incentive for a drug maker to do that — the patent on ketamine expired decades ago, and now it comes in the form of a generic drug.

So, while there’s a lot of research on its use and safety during surgery, there’s not as much on its use for depression. Doctors don’t know the best dosage, or the best way to administer it. And Gerard Sanacora, the director of Yale University’s Depression Research Program, says no one is officially tracking adverse effects.

“This is one of my largest concerns: there is no way of tracking whether there’s problems with the treatment, how many people are using this medication, if there’s an increased risk of anything at all,” Sanacora said.

A few years ago, Sanacora was part of an American Psychiatric Association panel that came up with some research-based guidelines and concerns for giving ketamine for depression. For instance, Yale offers the treatment to some patients, but those patients should not have a history of heart or neurological issues. That’s because ketamine can increase heart rate, blood pressure and the risk of seizure. People with a past history of substance abuse or psychosis also shouldn’t get the treatment.

Afable at the Serenity Health Clinic says they screen for these conditions. But media reports show that some clinics may not, and might be pitching the treatment as a wonder drug.

The research on ketamine for treatment-resistant depression also only studied short-term usage.

Michael Grunebaum, is a psychiatrist and researcher at Columbia University Medical Center; he’s published research showing ketamine can help with suicidal thoughts. He said the lack of oversight is a problem.

“No one really knows where that threshold is for safe long-term use,” Grunebaum said.

Depression can be a chronic condition that needs to be treated over the course of years. And the studies on long-term use really only look at people who have an addiction to ketamine and abuse it.

“There is evidence in the ketamine addiction literature that it can cause brain damage and serious injury to the bladder, the urinary system,” Grunebaum said.

But that’s when it’s used as a party drug, where doses are usually much higher than in a clinical setting. It’s not clear if those effects could also be seen with long-term clinical use.

That lack of certainty makes some mental health providers leery. Afable at Serenity Health said they gather patients’ medical records before authorizing treatment, and it’s common for a patient’s mental health care provider to call with questions.

“There have been a few that called us and just wanted to actually get a clearer picture on how we really do things, because there’s been a lot of centers that actually popped up and seem to be — the focus is just on you know, profit,” Afable said. “But I can tell you right now, this is not our focus.”

The Serenity Health Clinic offers ketamine treatments for however long patients need them, with a strong recommendation to get into therapy and find a psychiatrist. Afable says that after the first six IV treatments, patients download a mood tracker. Every day, they log how they feel, on a scale of one to ten.

“And if we see a trend that begins to actually start to drop, then we try to actually call them in and actually tell them that, hey, it might be time for you to actually receive a booster infusion,” Afable said.

Afable says about 90 percent of patients have come back for what they call “booster infusions” — another treatment after that initial six.

Gerard Sanacora, at Yale, said this practice of tracking patients with an app is better than some of clinics he’s heard about, where patients receive the treatments and are cut loose with no follow up afterwards.

Despite their concerns about the unregulated nature of use in private clinics, both Sanacora and Grunebaum said they’re hopeful about ketamine.

“There is really kind of a desperate need for new and effective treatments for that roughly a third of patients who don’t currently respond to the treatments we have,” Grunebaum said. “So ketamine can be, I think, sort of a last resort treatment for those patients.”

Afable at Serenity Health said the people that come to them have tried everything. Multiple antidepressants haven’t worked. Many have suicidal thoughts. He said his staff looks at the “fine line” between the risks of treatment, and its benefits: “Are we the the last straw that is standing between that person’s condition and them committing suicide?”