Ketamine for Adults With Treatment-Resistant Depression or Posttraumatic Stress Disorder: A 2023 Update
Authors: Barbara Angela M. , Xie Weiyi , Mahood Quenby , Hamson Angie 
Published: January 2024

What Is the Issue?

Many drug treatments are available for depression, but 22% of people in Canada with the condition have treatment-resistant depression (TRD). For people with TRD, standard drug treatments do not improve their symptoms or do not work for long, and their depression persists.

Posttraumatic stress disorder (PTSD) is a disabling mental health condition that affects about 9% of people in Canada in their lifetime. Few drugs are available for treating PTSD, none of which are considered effective.

Ketamine is a hallucinogenic drug used primarily for anesthesia. Ketamine has also been explored for other indications, such as TRD and PTSD, generating questions about whether it could be a treatment option for these conditions.

What Did We Do?

We conducted a review of the clinical effectiveness, cost-effectiveness, and evidence-based guidelines on the use of ketamine in adults with TRD or PTSD, to help guide decisions on the use of ketamine for managing these conditions.

An information specialist conducted a search of peer-reviewed and grey literature sources published in March 2022 or later. One reviewer screened citations and selected and critically appraised the included studies.

CADTH engaged a patient with lived experience of TRD who shared their experiences and perspectives on ketamine-assisted psychotherapy. These perspectives helped us to contextualize the literature and appreciate nuances of the experience.

What Did We Find?

Ketamine could lead to an immediate improvement in depressive symptoms and suicidal ideation compared to placebo or midazolam in adults with TRD. The longest follow-up was 90 days, and the longest lasting effect after a dose was 28 days. Serious side effects of ketamine — such as dissociation — were rare and short-lived, lasting hours, in adults with TRD.

It is uncertain if ketamine is an effective and safe treatment for symptoms of PTSD, due to little to no evidence suggesting its effectiveness or safety against placebo, midazolam, or opioids.

Most studies evaluated ketamine given intravenously, and we found limited evidence on intramuscular (IM), subcutaneous, and intranasal routes of administration. We found no studies on oral or sublingual administration of ketamine and no studies comparing the different ways that ketamine can be given for TRD or PTSD.

An economic evaluation found that IV ketamine was likely to be cost-effective compared to intranasal esketamine in adults with TRD from a health care perspective in the US. However, from a patient perspective, IV ketamine was unlikely to be cost-effective compared to esketamine, due to comparable levels of clinical effectiveness and lower costs of esketamine attributable to commercial insurance coverage and manufacturer assistance programs.

A US guideline on TRD suggests ketamine as augmentation to antidepressants. A US guideline on PTSD does not suggest the use of ketamine as therapy.

The patient contributor CADTH engaged for this review highlighted the benefits, stigma, and barriers of ketamine therapy, including financial implications.

What Does This Mean?

There is some clinical effectiveness and cost-effectiveness evidence and a guideline recommendation to support the short-term use of ketamine in adults with TRD.

Clinical effectiveness evidence and a guideline recommendation do not support the use of ketamine in adults with PTSD.

Future research is necessary to understand the effectiveness and safety of ketamine as therapy for TRD in larger populations over longer periods and for PTSD for any follow-up duration.

Decision-makers should consider offering ketamine in an equitable manner.