Ketamine’s fast action is particularly promising for suicide prevention, says Carlos Zarate of the NIMH. Instead of being committed to institutions for weeks of treatment, people who have just attempted suicide might be treated with ketamine and released in days or even hours. Zarate has found that ketamine seems specifically to affect the desire to attempt suicide, whether a person is clinically depressed or not (E. D. Ballard et al. J. Psychiatr. Res. 58, 161–166; 2014). That observation suggests that suicidal behaviour might be distinct from depression. Zarate is using ketamine to treat around 50 people with depression, some of whom have suicidal thoughts, to study these effects.

Early this year, his group will begin a multi-year study of people who have attempted suicide within the previous two weeks, imaging their brain activity and comparing them with people who attempted suicide more than a year previously and with people with depression who have never attempted suicide. Those who have recently attempted suicide will be enrolled in a clinical trial of ketamine; at the same time, Zarate hopes to learn more about what an actively suicidal brain looks like.