Suicide is a huge global problem, often taking place behind closed doors. Medical practitioners, across a number of countries, struggle to combat psychological disorders and appear poorly equipped to handle its associated complexities. Therefore, it comes as no surprise that over a million people commit suicide, every year, worldwide. Hopefully, with the discovery of new biomarkers, capable of predicting an individual’s risk of suicide, we can finally extend help to those desperate enough to take their own lives. But, could diagnosis be as simple as a blood test?
The team, led by H Le-Niculescu and D. F. Levey of the Indiana University School of Medicine, have recently published an article in Molecular Psychiatry, called Discovery and validation of blood biomarkers for suicidality.
They describe their hunt for a difference in genetic expression between perfectly healthy individuals and patients who had been diagnosed with bipolar disorder, a condition which increases an individual’s propensity towards suicide.
The group used what is known as a Convergent Functional Genomics (CFG) method, which ranked molecular biomarkers according to their ability to predict suicidality. The scientists acquired data from four different sources, using male patients from various medical facilities throughout Indiana:
- One Bipolar group
- Postmortem subjects, collected from the coroner’s office
- A follow-up group with bipolar disorder
- A follow-up group with psychosis
Levels of SAT1 (spermidine/spermine N1-acetyltransferase 1) expression was determined for each of the participants. Those involved in long-term testing (both bipolar and psychosis follow-up groups) had their SAT1 levels measured, along with a number of other biomarkers, which were then tabulated against the number of times they had been hospitalized, with or without a suicidal basis being the reason for the subject’s admission.
The results found four different biomarkers that could offer diagnostic potential, including MARCKS, MAP3K3, PTEN and SAT1. The authors suspect that SAT1, which was found to be the most potent indicator of a patient’s suicidality, could cause a process called apoptosis. Apoptosis is the cell’s programmed means of destroying itself, and can occur when the level of polyamines is reduced. Le-Niculescu, and his colleagues, suggest that SAT1 becomes overexpressed when a person is exposed to stressful stimuli. SAT1 then catalyses the breakdown of polyamines, which then causes cellular death (apoptosis).
According to Nature, Niculescu recently outlined the strong predictive value of SAT1, in determining suicide risk, which could be performed using a simple blood test:
“It was head and shoulders above the rest… [The work] opens a window into the biology of what’s happening.”
The authors then go on to discuss the impact of lithium, a medical drug that is found to reduce suicidality in psychiatric patients. The researchers refer to another study, performed in 2012, which found the miraculous drug to reduce levels of programmed cell death; it was also established that lithium treatment leads to an increase in gray matter within the brains of psychiatric patients. This is also supported by Niculescu’s own research, whereby another biomarker (CD24), which is also involved in apoptosis, was found to have been reduced.
Ultimately, the researchers found that the use of biomarkers, alongside regular clinical methods of diagnosing psychiatric disorders, enabled researchers to predict hospitalization with much greater accuracy, jumping from 65% to 80%.
On this basis, it would appear the authors have provided a speculative link between SAT1, cellular death and suicidal tendency.
The group correctly argue that patients with psychological disorders are in need of these diagnostic tools, as they infrequently share their suicidal ideation or intentions with others around them. If made part of a routine blood test, this could aid in the detection of “at risk” patients, who might then be approached and offered counseling and other psychiatric intervention.
According to The Daily Mail, Niculescu had this to say on the hidden nature of suicide:
“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.”
Suicide is the primary cause of death amongst psychiatric patients. Further clinical testing must be performed with a much larger cohort of patients, as admitted by the authors themselves. However, the ability to more accurately predict an individual’s suicidal tendencies, using something as simple as a blood test, is a very exciting prospect, indeed.
By: James Fenner