CHICAGO — Depression affects an estimated one in 15 adults, and is the leading cause of disability and loss of productivity in the world. It’s absolutely debilitating for some. But when conventional treatments fail, what’s next?

Ketamine, a drug usually found in the operating room (and sometimes on the street) may revolutionize the way depression is treated.

Ketamine has been in use in humans since the 1970s. You also may find it on the street. It’s a known club drug called “Special K,” taken for its hallucinogenic effects. And now — at a growing number of ketamine infusion clinics across the country — you’ll find patients rolling up their sleeves for a slow drip of what’s been found to be a fast-acting anti-depressant.

Anesthesiologist Dr. Bal Nandra opened his clinic, IV Solution, in downtown Chicago about a year ago. Administering the drug in small doses and what’s called “off-label” use, he treats patients struggling with a variety of mood disorders, including anxiety, PTSD, OCD and depression.

“Patients who have suffered for 20, 30 years of depression, who have tried multiple medication regimens, electroshock therapy even, we’ll see them respond to ketamine in just a matter of a few days,” Dr. Nandra said.

“We mostly deal with treatment-resistant depression, meaning depression that has failed two or more regimens or different classes of medications, as well as different therapies.” Dr. Nandra said.

That’s where ketamine seems to shine – for the estimated one-third of patients who experience little, if any, relief after trying more conventional treatments. And for suicidal patients, it can be life-saving.

“Ketamine has been shown to be well over 75 to 85, 90 percent effective against suicidal thoughts within minutes to hours,” Dr. Nandra said.

Jason Prinzo’s struggle with depression began as early as first grade, he said, due to issues with his my family, an abusive father and alcoholism. As he grew older, anxiety took its grip.

“If I would call my boss and my boss wasn’t able to pick up the phone, in a matter of seconds I would go from, ‘He can’t pick up, he must be mad at me, I’m going to lose my job, we’re gonna lose our house, my wife’s going to leave me, I’m going to be back living in a one-bedroom apartment,’” Prinzo said.

At the same time, the daily side-effects of the more conventional medications he was taking that left him equally debilitated, and Prinzo said he felt tired every day.

“It was affecting my personal life, my work life, my home life. It was bad,” Prinzo said.

At Dr. Nandra’s clinic, patients get six treatments up front spread out across the course of two weeks. During each session, blood pressure and heart rate are monitored, as the drug can increase both to dangerous levels.

“Ketamine is a dissociative drug. It allows patients to react less to their impulses and separates their thoughts and emotions and their reactions to those emotions,” Dr. Nandra said.

Jason Prinzo was in for his ninth infusion of ketamine.

“You feel like you’re dreaming a little bit. And I felt like I was moving a little slower and things were a little blurry but as soon as the treatment is over and you come down so to speak, a little tired afterwards, but within 45 minutes to an hour, I’m back to normal,” Prinzo said.

The therapy comes with a hefty price of $500 to $800 per treatment. And because the drug’s not FDA-approved to treat depression, patients pay out of pocket.

“There’s a stigma with mental illness that it makes you weak. I don’t think I knew how bad I was prior to starting the ketamine treatments. My drive is back again, and I feel like the light-hearted, fun guy that I am that the mental illness was trapping in,” Prinzo said.

Scientists used animal models to better understand how ketamine works in the brain. Unlike conventional anti-depressant medications developed to target chemical imbalances, ketamine appears to rapidly change how brain cells connect and communicate. The finding has sparked great interest: several pharmaceutical companies have ketamine-like drugs in the works. One is an intranasal solution psychiatrist Dr. John Zajecka recently tested at Rush University Medical Center.

“It’s one hit in each nostril. We’ve seen people who have responded. We’ve definitely seen people who get better,” Dr. Zajecka said.

University of Chicago Medicine psychiatrist Dr. Elliot Gershon has been practicing medicine for 50 years, and he’s recommended ketamine for some of his own patients.

“You have to be cautious about new developments and treatments, so even though I think this is looking good, I won’t be sure for a few years, and I don’t think the profession will be sure for a few years,” Dr. Gershon said. “But now for people who are particularly treatment resistant or particularly at risk of suicide, it’s reasonable to prescribe.”

What’s not known is how long the effect last. It varies from weeks to months depending on the patient. If symptoms return, patients often opt for ongoing maintenance doses, like Jason has.

But mental health experts are still debating whether maintenance doses are appropriate. A task force assembled by the American Psychiatric Association cited a lack of large-scale trials to determine the drug’s safety and efficacy for mood disorders, along with a lack of regulatory oversight of clinics, as reason for cautionary use.

“My recommendation is people need to have an informed consent if they are doing something like this. They need to be aware of all the risks and potential benefits,” Dr. Zajecka said.

Not all ketamine infusion clinics follow the same standards of care, so doctors do warn, you have to do your homework. Some of the most well-respected experts in mental health believe ketamine may revolutionize the way depression is treated. But they want to form a registry to track the drug`s use and learn more about how ketamine can help patients.

To learn more about IV Solutions, check out ketaminechicago.com

Log on to learn more about the American Psychiatric Association’s consensus statement.