brain scans MRI

Brain networks associated with suicide have been identified by examining brain images from the past two decades. The study published in Molecular Psychiatry found changes in the prefrontal cortex were important risk factors in suicidal thoughts and behaviours.

800,000 people die globally by suicide every year – one every 40 seconds. It is the second leading cause of death for those between 15 and 29 years old. Very little research has been done on what makes people from certain groups more vulnerable to suicidal thoughts, especially teenagers. One in three teenagers have suicidal thoughts, and of those 30% attempt suicide.

By looking at brain imaging studies over the past two decades the researchers hoped to build a more comprehensive picture of suicidal thoughts and behaviours in the brain. The researchers examined 131 studies which looked at over 12,000 individuals.

Two areas of the brain were found to play a crucial role. One in the generation of thoughts and the other in translating those thoughts into behaviours. The researchers then identified a network that mediates interactions between these two areas, the dACC (dorsal anterior cingulate cortex) and insula. By interrupting this network it is hoped that suicidal thoughts will be less likely to be translated into action. This provides a target for therapeutics for those most at risk of attempting suicide after experiencing suicidal thoughts.

The first area identified was the ventral prefrontal cortex (VPFC) which links several brain areas in the control of emotions. The second, the dorsal PFC and inferior frontal gyrus (DPFC/IFG), are the ‘action’ systems involved in decision making and controlling behaviour. Changes in these two systems were identified as a risk factor in suicidal thoughts and suicide attempts. The main differences were a reduced volume of the brain area and a decreased white matter integrity – the tissue which passes on messages between areas of the brain.

The combination of over 130 studies highlighted the importance of choosing the right participants as different groups are more at risk than others. In a large proportion of the studies, sex was not considered a variable or controlled for despite the varied needs of men and women. Men have higher lethality in suicide attempts, but women are more likely to attempt suicide. Of the 12,000 individuals, only one was identified as transgender, another group at increased risk of suicide. Rarely were adolescents exclusively looked at, despite brain differences found between adults and teenagers who had experience suicidal thoughts.

The collating of large data sets allows the identification of these brain differences in more vulnerable groups and how best to help them. Larger global studies are hoped to result in more effective targeting for suicide prevention, and to stop this deadly phenomenon in those most vulnerable.

Rona Strawbridge of Health Data Research UK (HDR UK) will be speaking at the upcoming Festival of Genomics on deriving risk markers of mental illness from the UK Biobank data resource. If you haven’t already registered you can do so here.