A single intravenous ketamine infusion may ease severe depression within hours and reduce suicidal thoughts within a day for some patients, according to a University of Connecticut review of clinical trials published in May in JAMA Psychiatry.
The findings point to a possible rapid-response option for people whose symptoms have not improved with standard treatments, a group at elevated risk of suicide and other serious outcomes. But the review also underscores why ketamine remains a closely watched therapy: its effects after one infusion appear temporary, it can be misused, and researchers say the evidence has limits.
The analysis reviewed 26 clinical trials involving more than 1,100 patients. About 626 received ketamine, while roughly 540 were in control groups. Most participants had major depressive disorder; smaller shares had bipolar depression or a mix of unipolar and bipolar depressive diagnoses.
Fast relief, but not a cure
Compared with placebo, one ketamine treatment reduced depression symptoms in as little as four hours and lowered suicidal thoughts within 24 hours, the review found. Patients also reported fewer depressive symptoms after a week, and reduced suicidal thoughts were seen for up to a month after one infusion.
Researchers found that repeated infusions produced similar reductions in suicidal and depressive symptoms by the end of treatment. Still, the authors said the benefit of a single infusion was generally short-lived, with depressive symptoms returning in nearly all patients after one treatment.
Ketamine was originally developed as an anesthetic. Unlike traditional antidepressants, which often take weeks to have their full effect, ketamine acts quickly through a different brain pathway involving glutamate, a neurotransmitter tied to mood and emotion.
“When all existing treatment options fail, patients with severe depression could consider ketamine infusions,” lead author Taeho Greg Rhee of the University of Connecticut School of Medicine told Fox News Digital, adding that IV ketamine is not FDA-approved for depression but may be used off label for severe cases or high suicide risk.
Safety and evidence gaps
The most common side effects reported in the review included headache, numbness, dissociation, nausea, dizziness and visual disturbances. Those effects were temporary and resolved within hours of the infusion, according to the review. More serious events, including hospitalization, suicide attempts and suicide, were rarer and were mostly judged unrelated to ketamine.
Outside experts cited in the report said the drug should be given only in closely monitored medical settings because of safety concerns and the potential for abuse or addiction. Dr. Lama Bazzi, a New York psychiatrist who was not involved in the study, said IV ketamine can be lifesaving for a small subset of patients in a major depressive episode or experiencing suicidal thoughts, but should be administered in clinics or other supervised settings.
The researchers also noted several limitations. In some trials, patients may have known they were receiving ketamine because of its noticeable effects, potentially shaping how they reported symptom changes. The individual studies were relatively small, and combining different trials makes it harder to apply the findings broadly.
For now, the review strengthens evidence that ketamine can act quickly in severe, treatment-resistant depression, while leaving unresolved how best to use it safely, how often it should be repeated and what its long-term outcomes are.
Comments (0)