Your sweat may reveal whether or not you're at risk of committing suicide, according to a clinical study published in the Journal of Psychiatric Research in September 2013.
German and Swedish researchers found a strong correlation between patients suffering from depression and experiencing hyporeactivity, a reduced ability to react to various stimuli. To test for hyporeactivity psychiatrists measure fluctuations in the patients blood pressure, circulation, and perspiration on their fingertips as the patient is listens to a pattern of tones. 97 percent of depressed patients who later committed suicide showed signs of hyporeactivity.
"We can determine very accurately whether a person risk committing suicide, which can revolutionise suicide prevention," says Lars-Hakan Torrel, an associate professor at Linkoping University and one of the researchers behind the study, said in a statement. "Everyone who has it is not suicidal—but almost all suicidal, depressed patients have it."
The study also shows that people with recurrent depression run the risk of becoming hyporeactive at some point later in life.