The discovery of a protein signature in women with a history of suicide attempts raises hopes we could soon have the tools to predict future risks of self-harm.

Past studies have identified potential markers of suicide risk in complex diagnostic procedures, such as brain scans, but the development of a quick and easy blood test could be a giant leap forward in getting help for those most at risk.

The research was conducted by a team of scientists from Binghamton University who piggybacked their work on a separate study being conducted on depression and anxieties in children.

A sample of 73 of the children's mothers was recruited for the study, who were interviewed to gather data on their health, life history, habits, and socio-economic statuses.

The sample were then divided into two matched groups – 34 who admitted to having inflicted injuries on themselves with an intent to die, and 39 who had no such history. All participants were given a clinical mental health assessment and also gave blood samples.

The researchers zoomed in on a protein in the plasma called brain-derived neurotrophic factor (BDNF), a type of growth factor known for its role in developing neural circuits.

Analysing this particular chemical was no arbitrary decision; altered neural plasticity has long been thought to play a role in the progression of suicidal ideation and depression.

This isn't even the first time BDNF itself has been linked to self-harm, with previous studies also finding reduced expression of the protein in the prefrontal cortex and hippocampus of autopsied brains from those who succeeded in their suicide attempts.

What the researchers did find is levels of BDNF are relatively lower in the peripheral blood of individuals who had attempted suicide far in the past, meaning the reduction is a long term characteristic.

"For this experiment, it was really important to understand that women with a history of suicide attempts who are not in a current suicidal crisis still have a BDNF marker that shows up lower," says researcher Brandon Gibb, the director of clinical training at Binghamton University.

In fact, the volunteers' last attempts were on average around 13 years prior to the study.

"This suggests that BDNF is not just a marker of a person's current suicidality or mood, but is actually a stable marker that may be able to predict risk of future suicide attempts."

Importantly, the comparative drop in BDNF levels wasn't a reflection of an overall reduction in protein in the body, or a measure of their current mood, past anxiety, or other potentially confounding factors.

That makes it a rather robust marker for potentially helping physicians make a better assessment of a patient's medical history. Further studies are required to determine whether similar measures can be made on men or other demographics.

The act of assessing risks of self-harm and suicide and then acting on it is a complex, ethically challenging process that has come under critical scrutiny in recent years.

While evidence of a history of suicide ideation and attempts could technically be considered a predictor, it's just as fair to say attempts are so common they aren't all that helpful.

With mental health still heavily stigmatised, having measures in place that offer support rather than risk exacerbating the problem with labels are also important.

Still, if implemented within the right healthcare framework, a quick and easy tool for assessing risk could potentially save lives.

"Testing BDNF levels can be incorporated into the standard blood test your primary care physician runs at annual checkups," says Gibb.

"Just like cholesterol levels help to determine levels of risk for heart disease, eventually doctors could have mental health tests that determine suicide risk."

This research was published in Suicide and Life Threatening Behaviour.

If this story has raised concerns or you need to talk to someone, here's a list where you may be able to find a crisis hotline in your country.