Depression affects about 17 million adults in the US. For many, antidepressants help.
However, for about one-third of sufferers, they either don't work or the side-effects outweigh the benefits.
Some psychiatrists say they have a solution, and it can relieve depression in just hours, instead of the days or weeks current drugs take.
It worked for one local woman, who asked we hide her identity. We'll call her Ann.
Ann says her world went dark in 2001 after her sister died of breast cancer.
Her own medical problems and other issues added to the burden. Her depression didn't resolve.
Ann recalls, "I didn't want anybody to know, so I became more and more isolated, avoided social situations. A lot of tears, a lot of crying."
A doctor prescribed anti-depressants but the side effects were too much to handle.
"I'd be taking miniscule doses of the drugs, which would take the edge off, but the side effects would start building up," Ann says.
"Before long, I'd be suffering more from the side effects than from the depression," she adds.
Ann spent almost a decade looking for the right treatment, and then was referred to psychiatrist Dr. Steve Levine of Princeton Health Psychiatric.
Last year, seeking new avenues of treatment for his patients, he learned of government tests with infusions of ketamine.
Ketamine is an FDA-approved anesthetic, primarily used to put people and pets asleep for surgery.
About 7 years ago, researchers at the National Institutes of Health discovered that a lower dose injection of ketamine could lift depression for some within just hours.
And it works differently than other anti-depressants.
Most boost serotonin, one of the mood chemicals in the brain.
Ketamine works on different receptors to repair the pathways depression has damaged.
Dr. Levine says, "What were seeing is that ketamine may actually restore that function, to repair those connections and form new connections very quickly.
He says there are no lasting side effects, though there can be hallucinations or strange sensations during the infusion.
For Ann, "A lot of geometric patterns, a lot of different colors. A lot of dizziness."
But they usually go away shortly after the infusion ends.
Ann now gets the treatment every 4-5 weeks, and says it's working.
Dr. Michael Thase of the University of Pennsylvania says ketamine has a lot of promise, but it comes with serious concerns.
"It's longer term benefits have not been proved and there are legitimate concerns about the safety," notes Dr. Thase.
And there is the potential for abuse. Ketamine is also known as "Special K," a popular and dangerous club drug. It is usually cooked down to a powder form, and snorted or smoked at much higher doses than depression patients receive.
Drug makers, such as Janssen Pharmaceuticals, are trying to make the infusion used in depression into a more accessible form, such as a pill or nasal spray.
"More people will have it in the medicine chests which means more teens, college students will be able to snitch it from the medicine chest," says Dr. Thase.
Dr. Levine says there's never been an adverse reaction reported with ketamine infusions, which are normally given under controlled conditions at medical infusion centers.
And he doesn't believe depression patients would be tempted to abuse ketamine. All are carefully screened before they begin the infusions.
Dr. Thase believes ketamine has opened up a new avenue of research.
A check of clinicaltrials.gov shows more than 30 studies underway right now to verify its success and to find new ways to deliver the drug safely.
The hope is to find something that acts like ketamine, without the potential for abuse.
In the meantime, Ann hopes it will continue to work for her.
"There's joy back in the things that I used to enjoy," she says.
Dr. Levine says he's treated about close to 60 patients from 22 states, and it has worked 75-percent of the time.
Initially, patients get a single infusion to see whether there is a response to the ketamine. If it does, patients generally receive 3 infusions a week at the start, then return every 3 to 6 weeks to maintain the effect.