People who killed
themselves had higher levels of specific gene
A substance that has
been found at elevated levels in the blood of people likely to kill themselves
could lead to a simple diagnostic test for suicide risk, researchers report
August 20 in Molecular Psychiatry.
Right now, clinicians
rely on people’s self-reported symptoms and feelings to decide who is in need
of immediate help, but a person intent on suicide isn’t always forthcoming. An
unambiguous blood test would show clinicians who is in immediate danger.
Outside researchers are
quick to say that the study should be interpreted cautiously. Nonetheless, the
findings are “amazingly strong for a small sample size,” says psychiatrist J. John
Mann of Columbia University and the New York State Psychiatric Institute.
The results came out of
a larger study on men with bipolar disorder. As part of that research, subjects
would visit a clinic every three to six months, where they would undergo psychological
testing and give a blood sample. Over the course of the study, nine men showed
a dramatic change between visits, first exhibiting no signs of suicidal
tendencies and later exhibiting many.
Several biological
molecules in the blood of these people changed along with this suicidal shift.
Most notable was a molecule made by the gene SAT1, which is
involved in cell death. For these nine men, high SAT1 activity
tracked with more suicidal thoughts and feelings, the team found.
To see if SAT1 might
track with suicide more generally, the team obtained blood samples from a
coroner’s office. SAT1 activity was found to be high in the
blood of nine different men who had killed themselves. “To our surprise, the
results were very strong,” Niculescu says.
SAT1 levels were also tied to hospitalizations
for suicidal behavior, the team found. In 49 different bipolar men, those with
higher SAT1 levels were more likely to be admitted than people
with low levels. Researchers don’t know whySAT1 levels are
correlated with suicide risk in this population.
“This is a very
interesting area and a very important question, but there are a lot of
technical issues with this study,” says neuroscientist Carl Ernst of McGill
University in Montreal. “There’s not a lot we can take from it at this stage.”
The study followed a
small number of men who were all on various medications. What’s more, the
algorithm used to identify SAT1 and other markers is somewhat
subjective, and it’s unclear whether men with bipolar disorder are a good proxy
for suicidal people in general, Ernst says. SAT1levels may have
nothing to do with suicide in women or in people with major depressive
disorder, for instance.
CITATIONS
H. L.-Niculescu et al.
Discovery and validation of blood biomarkers for suicidality. Molecular
Psychiatry. Published online August 20, 2013. Doi:
10.1038/mp.2013.95 [Go to]