UCL Institute of Mental Health


Peer self-harm could influence other young people to self-harm

21 December 2023

Risk of non-suicidal self-harm (NSSH) in young people is influenced by peer self-harm, a study by researchers affiliated to the UCL Institute of Mental Health suggests.

Young people sitting on a wall. Photo by Marlene Leppänen: https://www.pexels.com/photo/men-s-black-denim-pants-1019771/

The study, published in Acta Neuropsychiatrica, is the first experimental study to investigate what are termed ’suggestion effects’ after exposure to self-harm by people in participants’ social network. 

Just under 100 individuals aged 18–25 years with a recent history of self-harm were recruited for this research study. Participants were asked to imagine three scenarios, two of which were simulating peer NSSH. Their perceived ability to control urges to self-harm was measured pre- and post-exposure. 

After comparing the pre- and post-exposure data, the researchers found that participants’ ability to control urges to self-harm was significantly reduced following exposure to peer self-harm. This meant that exposure to peer self-harm had increased their urges to self-harm. 

The researchers had also designed a ’wash-out’ exposure, which invited participants to imagine a peer using an app to cope with anxious thoughts. This was then presented to the participant to neutralise any negative effects of their exposure to peer self-harm. 

Theraputic effects

The wash out exposure was found to have achieved its aim of restoring self-harm risk to baseline values - i.e. reducing urges to self-harm - which the researchers suggested show potential therapeutic effects of the wash-out in mitigating suggestion effects. 

However, the findings did not support a second hypothesis that more suggestible individuals - those identified as less resistant to peer influence - would be less able to control urges to self-harm after self-harm exposure. 

This indicates that their sample of young adults with a history of self-harm were susceptible to peer self-harm influences regardless of their individual suggestibility. The implication here is that when thinking about young people exposed to peer self-harm, there are no grounds to consider those who are more generally suggestible to be at greater risk of suggestion effects. 

Lead author, Dr Alexandra Pitman, of the Division of Psychiatry, said: “As far as we know this was the first experimental study to have investigated suggestion effects after self-harm, and represents an exciting collaboration between cognitive neuroscientists, psychiatric epidemiologists, psychiatrists and clinical psychologists. It triangulates the findings from epidemiological studies and demonstrates in real time how powerfully social influences operate on an individual level and in the immediate term. 

“Our findings regarding the washout intervention we developed are particularly exciting as this has the potential to be upscaled to benefit the large proportion of young people whose friends self-harm. We are working on this currently.” 

The project was specifically funded by the UCL Institute of Mental Health Small Grant Funding scheme to encourage collaborative and interdisciplinary work in mental health research. 

Other authors involved in the study included researchers at the UCL Institute of Cognitive Neuroscience, the UCL Division of Psychology & Language Sciences, the University of Birmingham and the University of Oxford. 

Professor Anthony David, Director, UCL Institute of Mental Health (IoMH), said: “This is an important study. We are increasingly aware that reports of suicide and self-harm can have a disturbing effect on young people even tipping them over into self-harm themselves. 

“While there are strict guidelines on media reporting, it is impossible to shelter everyone from the reality of such behaviours. This study provides evidence on how steps might be taken to mitigate these effects with a simple behavioural task. The report is bound to stimulate further work in the area including studies outside of the laboratory which might be shared with young people generally.” 


If you are worried about a young person exposed to peer self-harm, you can find access advice and support via this dedicated page on the IoMH website