Ketamine can rapidly reduce symptoms of PTSD and depression, new study finds

March 16th, 2024
Injectable medication

The drug ketamine can reduce the symptoms of post-traumatic stress disorder, or PTSD, and symptoms of depression in patients as early as a day after injection. That is the key finding of my team’s new meta-analysis, just published in the journal Annals of Pharmacotherapy.

Ketamine is an anaesthetic that is sometimes used as a substance of abuse but is increasingly being explored as a treatment for a range of mental health conditions.

We analyzed six randomized controlled trials representing 259 patients with moderate to severe PTSD. In all trials, about half were injected with ketamine. The rest received either salt water or the drug midazolam, a benzodiazepine like Xanax that is also used as an anaesthetic agent.

Patients receiving ketamine saw their PTSD symptoms reduced by about 25% both at one day and one week after therapy. But if patients received repeated injections over four weeks, PTSD symptoms declined by only 12%. Reduction of depression symptoms were more modest but still significant.

In most of these trials, patients only received a single shot; in the other two, they were given an injection at the same dose six or more times over two to four weeks. The benefits after the first injection were similar across studies, but it’s unclear how well additional doses of ketamine over time maintain these benefits.

Overall, the benefits of even a single ketamine injection occur rapidly but are modest in magnitude. The best regimen to maintain these benefits by reinjecting ketamine has not been determined.

Why it matters

PTSD, a debilitating mental health disorder, occurs when past trauma causes flashbacks, nightmares, depressed mood, anxiety and avoidance of activities that could trigger traumatic memories. Patients with PTSD are twice as likely to attempt suicide than the general population.

About 13 million Americans have PTSD in a given year, which translates to nearly 5% of the adult population. PTSD is caused by experiencing or witnessing a traumatic event. Many combat veterans have the disorder, as do survivors of physical assault, natural disasters, child abuse and sexual abuse. Those with moderate to severe disease cases lose an average of about three and a half days of work per month due to triggered symptoms or treatment for the illness.

Trauma-focused psychotherapy – techniques that help patients recall, process and respond to traumatic memories – is the treatment of choice for PTSD, but it can take several weeks to see benefits, and not all patients respond.

For these people, antidepressants such as paroxetine, sertraline and venlafaxine are recommended as alternatives, or as an addition to psychotherapy.

But like psychotherapy, these drugs may not work for a while – about five to eight weeks – unlike ketamine, which seems to begin working almost immediately. That said, the reduction in PTSD and depression symptoms over time following ketamine injection is about the same as what the traditional antidepressants provide once they take effect.

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At Pain Spa, Dr Krishna is highly experienced in the appropriate use of Ketamine for the management of patients with chronic pain and certain other conditions. Please email us for further details at if you are interested in having a consultation with Dr Krishna.