'Biological signal' of suicide risk found in blood

Researchers have discovered a series of RNA biomarkers in blood that could be used to develop a test to predict the risk of a person committing suicide.

The research, published in the journal Molecular Psychiatry, analyzed a large group of male patients from four cohort studies over a three-year period. All patients were diagnosed with bipolar disorder.

Psychiatrists and other researchers from the Indiana University School of Medicine conducted a series of interviews with the patients.

There was one interview at the baseline of the study, followed by up to three testing visits - when blood was also taken from the patients, every three and six months.

Each testing visit involved the patients being given a psychiatric score using the "Hamilton Rating Scale for Depression-17." This scale includes a rating for suicidal ideation (SI) to determine level of suicidal feeling. Blood was then taken from the subjects of the study.

The researchers analyzed the blood of participants who reported a dramatic shift from feeling no suicidal thoughts at all, to strong suicidal ideation.

Results of the analysis revealed significant gene differences between the patients who experienced high states of suicidal thinking and the people with low states of suicidal feeling.

'SAT1 biomarker' for suicide

The researchers say they found that the marker SAT1, alongside a series of others, was a strong "biological signal" associated with suicidal thoughts.

In support of their findings, the researchers analyzed blood samples taken from suicide victims from a local coroners office. The blood samples revealed that some of the same markers were elevated.

The researchers then analyzed blood test results from two other groups of patients. They found that high blood levels of these specific biomarkers were linked with future suicide-related hospitalizations, and hospitalizations that took place before the blood tests.

Dr. Alexander Niculescu, associate professor of psychiatry and medical neuroscience at the Indiana University School of Medicine, says:

"Suicide is a big problem in psychiatry. It is a big problem in the civilian realm, it is a big problem in the military realm and there are no objective markers.

There are people who will not reveal they are having suicidal thoughts when you ask them, who then commit it and there's nothing you can do about it. We need better ways to identify, intervene and prevent these tragic cases."

Dr. Niculescu talks more in a UI School of Medicine YouTube film:

According to CDC statistics on self-inflicted injury and suicide, in 2010 there were:

• 713,000 emergency department visits for self-inflicted injury


• 38,364 suicidal deaths.

"Suicide is complex. In addition to psychiatric and addiction issues that make people more vulnerable, there are existential issues related to lack of satisfaction with one's life, lack of hope for the future, not feeling needed, and cultural factors that make suicide seem like an option," says Dr. Niculescu.

'Further research needed' on females

The researchers note that although they are confident that these biomarkers could be used for future blood tests to detect suicide risk, the subjects in the study were all male.