The drug takes effect within hours.

Ketamine — a type of anaesthetic — has anti-suicidal effects within hours of administration, new research finds.

The drug performed better than a commonly used sedative called midazolam.

The drug could be useful for those experiencing suicidal thoughts.

Dr Michael Grunebaum, the study’s first author, said:

“There is a critical window in which depressed patients who are suicidal need rapid relief to prevent self-harm.

Currently available antidepressants can be effective in reducing suicidal thoughts in patients with depression, but they can take weeks to have an effect.

Suicidal, depressed patients need treatments that are rapidly effective in reducing suicidal thoughts when they are at highest risk.

Currently, there is no such treatment for rapid relief of suicidal thoughts in depressed patients.”

The study compared ketamine with midazolam in a group of 80 people experiencing suicidal thoughts.

Those given ketamine showed a greater reduction in suicidal thoughts.

Researchers found that the beneficial effects of ketamine persisted six weeks later.

Dr Grunebaum said:

“This study shows that ketamine offers promise as a rapidly acting treatment for reducing suicidal thoughts in patients with depression.

Additional research to evaluate ketamine’s antidepressant and anti-suicidal effects may pave the way for the development of new antidepressant medications that are faster acting and have the potential to help individuals who do not respond to currently available treatments.”

The study was published in the American Journal of Psychiatry (Grunebaum et al., 2017).