There are key networks within the human brain that interact to increase the risk a person will contemplate — or attempt — suicide.

A study, published recently in the journal Molecular Psychiatry, reveals how a team of researchers carried out a review of two decades' worth of scientific literature relating to brain imaging studies of suicidal thoughts and behavior. Researchers pored over a total of 131 studies covering more than 12,000 individuals. What researchers were looking for were alterations in brain structure and function that might increase an individual's suicide risk.

Suicide is a horrific "disease" that kills one person every 40 seconds worldwide. It's the second leading cause of death globally among 15- to 29-year-olds. More than 800,000 people die by suicide every year around the world.

"Imagine having a disease that we knew killed almost a million people a year, a quarter of them before the age of thirty, and yet we knew nothing about why some individuals are more vulnerable to this disease," Dr. Anne-Laura van Harmelen, co-first author from the University of Cambridge, said. "This is where we are with suicide. We know very little about what's happening in the brain, why there are sex differences, and what makes young people especially vulnerable to suicide."

Researchers looked for evidence of structural, functional and molecular alterations in the brain that could increase risk of suicide. They identified two brain networks (and the connections between them) that appear to play an important role.

These two brains networks are the medial and lateral ventral prefrontal cortex and the dorsal prefrontal cortex and inferior frontal gyrus system.

Located towards the front of the brain, the medial and lateral ventral prefrontal cortex and their connections to other brain regions are involved in emotion. Alterations in this network may lead to excessive negative thoughts and difficulties in regulating emotions. These actions stimulate thoughts of suicide.

Alterations to the dorsal prefrontal cortex and inferior frontal gyrus system might influence suicide attempt, partly due to its role in decision making, generating alternative solutions to problems and controlling behavior.

The study suggests that the structure, function or biochemistry of both networks might lead to situations where an individual thinks negatively about the future. This individual will also be unable to control his thoughts, which might lead to situations where an individual is at higher risk of suicide.

More women aged 10-14 committed suicide this year. Hasty Words/Pixabay

"The review provides evidence to support a very hopeful future in which we will find new and improved ways to reduce risk of suicide," Prof. Hilary Blumberg said. "The brain circuitry differences found to converge across the many studies provide important targets for the generation of more effective suicide prevention strategies."