Being bullied when young is associated with widespread changes in the adolescent brain, which may influence future mental health, according to the largest brain scanning study of its kind.
Being on the receiving end of persistent or severe bullying , and has been linked with .
While previous research has identified regions of the brain that are affected by bullying, our understanding of its impact over time remains limited.
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To investigate further, at the Royal College of Surgeons in Ireland and his colleagues analysed data from 2094 people. At ages 14, 19 and 22, each person had their brain scanned using MRI and completed questionnaires about their experiences of bullying, such as name-calling, social exclusion and physical assaults. The frequency of events was used to give each person a 鈥渂ullying victimisation鈥� score.
The researchers found that bullying seems to affect 49 brain regions, particularly those responsible for memory, learning, motor movements and emotional regulation.
Enlargements in the subcortical regions were particularly intriguing, says Connaughton. The prefrontal cortex receives messages from subcortical regions about what is going on in the body and environment. It acts as a governing system, selecting what is important and what to ignore.
Increased subcortical volume might mean that the impulses going to the prefrontal cortex are stronger than in other people, says Connaughton. 鈥淪o it might be tougher for the governing system to regulate everything, making it more difficult later in life to control emotions.鈥�
The hippocampus, which plays a crucial role in regulating our response to stress, also seems to reduce in volume in response to bullying. Alterations may disrupt hormonal regulation, potentially impairing the body鈥檚 ability to manage stress later in life. Previous research has shown that hippocampus structure can affect the risk of depression in adults.
鈥淭his research confirms what we鈥檝e long suspected 鈥� that聽bullying聽has lasting, profound effects on children鈥檚 lives, well into adulthood,鈥� says at the UK charity the Anti-Bullying聽Alliance.
The research also uncovered differences between how male and female brains respond to bullying. In females, it was associated with greater increases in volume in areas such as the nucleus accumbens and amygdala, compared with bullied males. These areas are integral to how we process emotional and stressful responses. These changes may be more pronounced in females because of the type of bullying experienced, which tends to involve more manipulation and exclusion, says Connaughton.
Conversely, males tend to experience more physical bullying, which may explain why the team saw more changes in regions associated with spatial awareness and physical coordination. Connaughton points out that we don鈥檛 know whether the differences result from the way female and male brains respond to bullying, perhaps because of differences in hormonal profiles, or whether they are changing in response to the types of bullying.
The work underscores the need for people like doctors and teachers to be sensitive to the effects that bullying has on both sexes. 鈥淭he fact that girls are more severely impacted, particularly in areas of emotional processing, shows we need to better understand why this is happening 鈥� and to do that, we must listen to their experiences,鈥� says Evans.
Whether these brain alterations are permanent or reversible is the big question, says Connaughton. The brain undergoes changes throughout life, but adolescence is a particularly critical period. Lots of transformations occur at this time as the brain reorganises itself. During this stage, it is more susceptible to stress, reacting more acutely , for instance, which is released in response to bullying.
It is also less resilient to the impacts of stress. Adults are generally better able to recover from stressful experiences, in part because their prefrontal cortex helps supress negative memories that are no longer important by helping the brain 鈥渨rite鈥� and store new ones. However, during adolescence, meaning it is more challenging to suppress and replace negative memories.
This heightened sensitivity of the adolescent brain to stress may explain why bullying can lead to changes linked to negative mental health in adulthood. But not all changes are bad. 鈥淪ome people experience bullying and become more resilient, it would be interesting to try to find out why that is,鈥� says Connaughton.
Perhaps there is a threshold, whereby a certain amount of stress can lead to resilience but going beyond this leads to negative consequences, or it may be that other environmental or genetic factors put certain people at more risk of experiencing long-term health effects after bullying.
In an earlier , authors and at the University of Ottawa in Canada said they hoped a better understanding of it would mean those who have been bullied get help to develop ways to cope with stress later in life.
Cognitive behavioural therapy can help people adapt a more resilient mindset, says Connaughton. 鈥淚t would be ideal if you were able to identify a critical age range where brain changes are linked to later psychopathology and then you could target resources and interventions to that age group.鈥�
Need a listening ear? UK Samaritans: 116123 (); US 988 Suicide & Crisis Lifeline: 988 (). Visit聽聽for other countries
bioRxiv
Article amended on 23 October 2024
This article has been changed to correct where Michael Connaughton works.
