New research suggests a potential therapeutic use for ketamine. 

A study from the University of the Sunshine Coast (USC) has found that oral doses of ketamine can lower suicidal ideation in patients with chronic suicidal thoughts.

Ketamine is an anaesthetic discovered in the 1950s that is often considered as a horse tranquilliser or illicit party drug, but increasing amounts of research suggest it is capable of having positive effects on mental health issues, treating severe depression, among other conditions. In the US, regulators have already approved a ketamine-based nasal spray as a treatment for depression.

In the latest study from the USC, researchers built on previous work that showed the drug can quickly reduces suicidal ideation in people who experience such thoughts.

While most earlier studies had delivered ketamine by intravenous (IV) administration, researchers say there is an easier way.

“An oral form of ketamine that can be administered with ease, and potentially on a more frequent basis, is … an attractive option for the treatment of suicidal ideation,” the USC researchers wrote in their new study.

“However, very few studies have explored the feasibility of low-dose oral ketamine in treating suicidality.”

USC psychiatrist Adem Can ran a trial in which 32 adult patients were given mild, sub-anaesthetic doses of oral ketamine over six weeks, mixed into orange juice. The dosages increased over the course of the experiment.

All participants had previously suffered chronic suicidality – ongoing suicidal thoughts that linger in the mind but may never rise to acute or extreme risk of suicide.

“These patients had lived with suicidality for a very long time and presented a range of psychiatric conditions, including mood, anxiety and personality disorders, and many of them had lost hope of recovery,” Dr Can says.

Even so, the experiment saw some substantial and rapid-acting responses.

“On average, patients experienced a significant reduction in suicide ideation, from a high level before the trial to below the clinical threshold by week six of the trial,” Dr Can says.

“In medicine, this response rate is significant, particularly given it was experienced by patients with chronic suicidality, which can be difficult to treat.”

After six weeks, suicidal thoughts had dropped below what is considered a clinically significant level of suicidal ideation for over two-thirds (69 percent) of the group. Side effects included decreased energy and fatigue, restlessness, anxiety, and dizziness.

“To the best of our knowledge, the current study is the first to explore the feasibility, safety and tolerability of oral ketamine on chronic suicidality in patients who presented with a range of psychiatric conditions including mood, anxiety, and personality disorders,” the authors wrote.

“Overall, oral ketamine led to significant short-term and prolonged improvements in suicidal ideation, affective symptoms, well-being and socio-occupational functioning in this sample of adults with a history of chronic suicidality and [major depressive disorder].”