Could a blood test predict whether a person is at risk of committing suicide? For the first time, a set of proteins in the blood have been linked to suicidal behaviour. People who commit suicide appear to share a number of biological traits, regardless of any underlying conditions. This hints that suicidal behaviour may be a distinct disorder.
To investigate, Alexander Niculescu of Indiana University in Indianapolis and colleagues collected blood from the cadavers of nine men who had bipolar disorder and suicidal tendencies, and nine with bipolar but no suicidal thoughts, and compared levels of all the genes expressed in their blood.
Four genes were expressed at significantly higher levels in the blood of people who had been suicidal. Some proteins that these genes code for are known to be involved in stress and cell death.
The team then measured levels of these proteins in 42 people with bipolar disorder who had been hospitalised for attempting suicide. People who had been hospitalised more often tended to have higher levels of the proteins.
Finally, the team collected blood from the cadavers of a further nine men who had committed suicide without bipolar, and found elevated levels of some of the proteins.
Ghanshyam Pandey at the University of Chicago says that the study is unique in that it compares bipolar suicide victims with non-suicidal people with the same condition. But the test will need to be performed on many more patients, he says, as well as on suicidal people who have other disorders such as depression or schizophrenia.
Niculescu’s team is now looking for the proteins in more people with a range of underlying conditions, and in women, with the hope of developing a blood test to identify people at risk of suicide.
Written by Sara Reardon
Journal reference: Molecular Psychiatry, DOI: 10.1038/mp.2013.95
© Copyright Reed Business Information Ltd.