College Fellow leads study identifying brain networks that play a crucial role in suicide risk

Anne-Laura and an international team of researchers, including Lianne Schmaal at Orygen Melbourne and Hilary Blumberg, MD at Yale have identified key networks within the brain which they say interact to increase the risk that an individual will think about – or attempt – suicide..

The team carried out a review of two decades’ worth of scientific literature relating to brain imaging studies of suicidal thoughts and behaviour. In total, they looked at 131 studies, which covered more than 12,000 individuals, looking at alterations in brain structure and function that might increase an individual’s suicide risk.

Writing today in Molecular Psychiatry, the researchers say that their review of existing literature highlights how little research has been done into one of the world’s major killers, particularly among the most vulnerable groups.

“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,” said Dr Anne-Laura van Harmelen, co-first author from the University of Cambridge. “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.”

In 2013, it was estimated that 9.3 million adults 18 years and older in the United States had suicidal thoughts and 1.3 million attempted suicide. In addition, a 2011 report estimated that 13% of adolescents planned a suicide attempt (SA) in the previous year and 8% attempted suicide. Unfortunately, suicide death rates have continued to rise.

Combining the results from all of the brain imaging studies available, the 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. The first of these networks involves areas towards the front of the brain known as the medial and lateral ventral prefrontal cortex and their connections to other brain regions involved in emotion. Alterations in this network may lead to excessive negative thoughts and difficulties regulating emotions, stimulating thoughts of suicide. The second network involves regions known as the dorsal prefrontal cortex and inferior frontal gyrus system. Alterations in this network may influence suicide attempt, in part, due to its role in decision making, generating alternative solutions to problems, and controlling behaviour.

The researchers suggest that if both networks are altered in terms of their structure, function or biochemistry, this might lead to situations where an individual thinks negatively about the future and is unable to control their thoughts, which might lead to situations where an individual is at higher risk for suicide.

The majority of studies so far have been cross-sectional, meaning that they take a ‘snapshot’ of the brain, rather than looking over a period of time, and so can only relate to suicidal thoughts or behaviours in the past. The researchers say there is an urgent need for more research that looks at whether their proposed model relates to future suicide attempts and at whether any therapies are able to change the structure or function of these brain networks and thereby perhaps reduce suicide risk.

The review highlighted the paucity of research into suicide, particularly into sex differences and among vulnerable groups. Despite suicidal thoughts often first occurring as early as during adolescence, the majority of studies focused on adults.

“There are very vulnerable groups who are clearly not being served by research for a number of reasons, including stigma and the need to prioritise treatment,” said van Harmelen. “We urgently need to study these groups and find ways to help and support them.”

In 2018, the researchers launched the HOPES (Help Overcome and Prevent the Emergence of Suicide) study, supported by the mental health research charity MQ. HOPES brings together data from around 4,000 young people across 15 different countries in order to develop a model to predict who is at risk of suicide.

Published on 2nd December, the article is freely available at: https://www.nature.com/articles/s41380-019-0587-x​

The research was supported by the mental health charity MQ Brighter Futures Award Program, National Institutes of Health, Department of Veterans Affairs, NHMRC, Royal Society Dorothy Hodgkin Fellowship, American Foundation for Suicide Prevention, Brain and Behavior Foundation, Robert E. Leet and Clara M. Guthrie Patterson Trust, and For the Love of Travis Foundation.

About Anne-Laura Van Harmelen:

Anne -Laura van Harmelen is a Royal Society Dorothy Hodgkin Fellow and Senior Research Associate at the Department of Psychiatry, University of Cambridge and a Fellow at Lucy Cavendish College. She directs the Risk and Resilience Group. The group aims to investigate why some children and adolescents develop mental health problems, and others do not. Her work is funded by the Royal Society and MQ.

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