In small doses ketamine is a potent antidepressant, psychiatrist Dennis Charney and a team at Yale University reported in 2000. In a small study, the compound was especially helpful for people with treatment-resistant depression for which therapy and drugs don't work. Ketamine brought relief almost immediately, and at the low doses Charney used, it caused only mild to moderate dissociation and no major delusions.
Charney, now dean of the Mount Sinai School of Medicine in New York City, thinks ketamine could serve as an alternative to electroconvulsive therapy, the current treatment of last resort. He envisions patients receiving a series of ketamine injections that would keep them depression-free for a month or more. During that window of opportunity, other drugs and therapies would be introduced to ward off relapse, perhaps aided by an occasional ketamine booster.
In a small study published last year, a single ketamine injection dramatically lifted patients’ depression within 24 hours. After multiple doses over two weeks, 9 of 10 patients showed significant improvement. One remained stable for more than three months. “It’s pretty amazing to these patients,” says Rebecca Price, a graduate psychology student at Rutgers University and lead author of the study. “They can’t even remember not being depressed—and then they get this little respite.” Charney says it will take at least several years to conduct enough large, controlled studies for federal drug approval.