May 2, 2014
By Medical Discovery News
The 10th leading cause of death in America is completely preventable – suicide. In 2010, 38,364 people died by suicide, more than chronic liver disease, septicemia, and Parkinson’s disease.
While strongly linked to depression, there are not always clear warning signs that someone is about to commit suicide. Unlike a viral or bacterial infection where there can be a number of signs like changes in body temperature, white blood cells, and signaling molecules, there is no simple clinical test to diagnose suicidal tendencies. Now, new research is working toward a blood test using biomarkers that may identify those likely to commit suicide.
Biomarkers are biological materials that are seen under specific conditions. For example, during a viral infection proteins called cytokines are produced by the human body to help defend cells and tissues from the virus. Identifying these proteins is a signature of viral infection. The challenge is that these signatures change over the course of the infection and different viruses can produce different signatures. Scientists have been working extensively to use this concept of biomarkers to help with the early detection of other diseases from cancer to Alzheimer’s.
Researchers at the University of Indiana want to design a simple blood test to detect a specific biomarker to identify those who might be at risk for suicide. They have been looking for protein biomarkers that can distinguish different psychological states. For example, can specific biomarkers tell if someone with bipolar disorder is in a high or low mood? In this recent study, researchers looked for biomarkers in individuals contemplating suicide. Every three to six months, they interviewed and drew blood from their subjects – 75 men with bipolar disorder – and rated their risk of suicide from low to high. Several proteins in the blood varied with these mood swings but one in particular caught researchers’ attention. The protein SAT1 was present in all of those with high indications of suicidal thoughts. SAT1 plays a role in the body’s response to stressful situations.
They then tested suicide victims, grouping them by age and gender, and found high levels of SAT1 in all of them. Finally, they took blood samples regularly from about 80 men with either schizophrenia or bipolar disorder. The study showed higher SAT1 levels in those who were later hospitalized for suicidal behavior. The presence of elevated SAT1 was more than 80 percent predictive of hospitalization. Overall, these are promising results.
SAT1 is not an absolute signature for suicide because many things that can affect its levels. And like any complex behavior, there are a multitude of factors involved. Other biomarkers will need to be identified to create a biosignature for suicide. But this is an exciting discovery that may be used to prevent the tragic deaths of many people in the future.
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Pamela K. Bond 