A large international study, led by QIMR Berghofer researchers, has found a new link between brain structure and the risk of suicide attempt among patients with depression, shedding light on the biological basis for the behaviour.
The global collaboration of more than 60 scientists found differences in three key brain regions in people who suffer from depression and have attempted suicide in the past, compared to the brains of healthy controls and people who suffer from depression but had no history of suicide attempt.
The research findings have been published in the journal Biological Psychiatry.
The researchers examined brain imaging and clinical data from almost 19,000 people, including 694 people who had attempted suicide, 6,448 people who were diagnosed with depression but had not attempted suicide, and 12,477 healthy controls.
Senior researcher Dr Miguel E. Rentería from QIMR Berghofer’s Genetic Epidemiology group said their findings suggest that people who had attempted suicide had a slightly smaller thalamus and right pallidum, as well as lower surface area of the left inferior parietal lobe, compared to the other groups.
“The most significant difference was in the size of the thalamus – one of the brain’s processing centres for sensory signals, which has historically been viewed as a passive gateway in the brain. We found the left and right thalamic regions in the brains of people who had attempted suicide were slightly smaller than in people in the other two groups. There was no difference in the size between the two groups with no history of suicide attempt,” Dr Renteria said.
“We found the difference in the architecture of the pallidum was only obvious on the right hemisphere in people who had attempted suicide. Conversely, the small reduction in surface area of the inferior parietal lobe was mostly observed on the left cortex.
“Our research provides a better understanding of the biological basis of suicidal behaviour, and is an important first step towards developing more effective and targeted suicide prevention and intervention strategies and treatments in the future.”
MRI scans and clinical measurements were gathered from 18 international research groups, in a collaboration with the ENIGMA consortium’s working group on major depressive disorder.
Study senior co-author Associate Professor Lianne Schmaal, head of the Mood & Anxiety Disorders Research Program at Orygen and Centre for Youth Mental Health at the University of Melbourne said the project was the largest and most comprehensive neuroimaging study of suicide attempt to date.
“It’s still not certain what causes these small structural changes, whether it is the behaviour that causes the brain regions to shrink or the other way round, but it highlights several brain areas that we need to better understand,” Associate Professor Schmaal said.
“Suicidal behaviour is varied and complex, and is a considerable health concern in both developed and developing countries. It is more common in people living with mental illness. If we can expand research into the driving mechanisms of suicide, we can hopefully help reduce its personal and societal burden.”
The lead researcher on the study, Mr Adrian Campos from QIMR Berghofer’s Genetic Epidemiology group, said it was the first large-scale study to find a robust association between brain structure and suicide attempt risk.
“The strength of this international study is in the numbers – and that can only be achieved through strong collaborations between researchers around the world,” said Mr Campos, who has been undertaking the research as part of his PhD studies.
“Previous studies have had quite small samples sizes but by examining the brains of almost 19,000 people from Europe, North America, Asia and Australia, we could provide strong statistical evidence of the role of brain structure in suicidal behaviour.
“Although our research included participants from over four continents, we would also like to broaden the study to Africa and South America to provide as full a picture of the role of brain architecture as possible.”
More than 60 co-authors from 18 different research groups contributed to the study through the ENIGMA (Enhancing Neuro-Imaging Genetics through Meta-Analysis) consortium.
The study can be accessed on the Biological Psychiatry website.
Close to 800,000 people worldwide die to suicide every year according to the World Health Organization, and for every suicide there are many more people who attempt to take their own lives. Suicide was the third leading cause of death in 15-19-year-olds globally in 2016.
The World Health Organization cites a prior suicide attempt as the single most important risk factor for suicide in the general population.
For help contact:
Kids Helpline – 1800 55 1800 – Child and adolescent help
Headspace – Online counselling
Lifeline – 13 11 14 – 24-hour Australian crisis counselling service
Suicide Call Back Service – 1300 659 467 – 24-hour Australian counselling service
Beyond Blue – 1300 22 4636 – 24-hour phone support, an online chat service and links to resources and apps