Searching the brain for reasons for suicide – using ketamine.

Nature looks at a new ketamine study of the brains of people who attempted suicide:

Fewer than 10% of people with depression attempt suicide, and about 10% of those who kill themselves were never diagnosed with any mental-health condition.

Now, a study is trying to determine what happens in the brain when a person attempts suicide, and what sets such people apart.

The project, which launched this month, will recruit 50 people who have attempted suicide in the two weeks before enrolling in the study. Carlos Zarate, a psychiatrist at the US National Institute of Mental Health in Bethesda, Maryland, and his colleagues will compare these people’s brain structure and function to that of 40 people who attempted suicide more than a year ago, 40 people with depression or anxiety who have never attempted suicide and a control group of 40 healthy people. In doing so, the researchers hope to elucidate the brain mechanisms associated with the impulse to kill oneself.

Zarate’s team will also give ketamine, a psychoactive ‘party drug’, to the group that has recently attempted suicide. Ketamine, which is sometimes used to treat depression, can quickly arrest suicidal thoughts and behaviour — even in cases when it does not affect other symptoms of depression. The effect is known to last for about a week.

To some researchers, such findings suggest that ketamine affects brain circuits that are specific to suicidal thinking.