Young women who engaged in non-suicidal self-harm had significantly different brain activity compared to healthy women when receiving positive and negative feedback on social media, and the severity of the brain differences reflected the severity of their symptoms. The new study was published in the journal Translational Psychiatry.
Self-harm without suicidal intent (known as non-suicidal self-injury (NSSI)) is alarmingly common among young people, affecting an estimated one in five adolescents worldwide, and is particularly prevalent among women. This refers to intentionally harming oneself, such as cutting or burning, without intending to end one’s life. Exposure to social media is associated with increased risk of self-harm among young people, especially girls. Until now, the biological reasons for this vulnerability were not well understood.
Social media platforms are specifically designed to trigger a reward response. When you receive a like or positive comment, the same brain areas involved in processing monetary rewards are activated. Therefore, the researchers were particularly interested in whether the brain’s reward system – a network of structures that processes pleasure and reinforces behavior – might be altered in young women with NSSI during social media interactions.
The team, led by Stella Nicolau from the University of Barcelona, recruited 91 young women between the ages of 18 and 30, all of whom had active Instagram accounts. After excluding a small number of participants due to poor scan data or excessive head movement, the final analysis divided 88 participants into three groups. A clinical group of 29 women diagnosed with both NSSI and borderline personality disorder, an asymptomatic group of 27 women with NSSI but no other psychiatric diagnoses, and a healthy control group of 32 women with no history of self-harm.
Before the study, the researchers followed participants’ Instagram accounts and selected 15 personal photos to use as stimuli. Participants were told that other volunteers would rate their photos, and during the brain scan they received comments, some positive and some negative, that they believed were real. All participants underwent brain imaging using functional MRI while completing this task, which simulates real-life Instagram interactions.
The results revealed clear patterns associated with severity. Clinical groups showed that the brain’s responses were significantly blunted in key reward areas, including the nucleus accumbens, caudate nucleus, and medial frontal cortex, when receiving positive and negative feedback. Surprisingly, receiving a negative comment actually increased activity in the same reward area. This suggests that negative social feedback may be perceived as more appealing to women with a history of more severe self-harm.
The brain responses of the asymptomatic group were somewhere between those of the healthy control group and the clinical group, suggesting that what the researchers describe as a “continuum of severity” is mapped to the reward system. These women responded similarly to healthy controls to positive comments, but similarly to the clinical group to negative comments, indicating a selective vulnerability to negative feedback online. Behaviorally, the asymptomatic group rated negative comments as significantly more unpleasant than the control group.
Importantly, all three groups reported similar overall levels of Instagram use and addiction. In other words, brain differences cannot be explained solely by the amount of time participants spent on social media. However, the researchers found a significant association. In both groups who participated in the NSSI, reduced brain activity in the reward center was directly correlated with higher scores on the Instagram addiction test. This association was completely absent in healthy controls, suggesting that problematic social media use in patients with NSSI is linked to altered neural processing.
The authors write: “These findings reflect a continuum of severity mapped to reward systems, highlight potential targets for intervention, and highlight the need to address social media interactions in NSSI treatment.”
Some important limitations should be noted. For example, the negative comments used in the experiment were intentionally mild due to ethical constraints, so the observed brain responses may be an underestimate of what happens during real-world online cyberbullying. Additionally, because this study focused only on women and utilized Instagram, the results may not necessarily generalize to men or users of other platforms such as TikTok.
The study, “Reward-related neural activation during social media exposure in young women with non-suicidal self-harm: Evidence for a continuum of severity in the reward network,” was authored by Stella Nicolau, Anna Julia, Daniela Otero, Carlos Schmidt, Juan Carlos Pascual, Joaquín Soler, Josep Marco-Parales, and Daniel Vega.
