Discussion

Continuation of NSSI beyond adolescence appears to be a risk factor for increased depressive symptoms and urge to self-injure as well as more frequent self-injury during the pandemic. Nonetheless, even with early cessation of self-injury in adolescence, a self-reported increase in emotional burden and urge to self-injure is evident during the pandemic. On the one hand, the results of our survey support prior findings that university students with a history of self-injurious behaviours in general are at high risk for experiencing distress during the COVID-19 pandemic lockdown.^{Reference Patsali, Mousa, Papadopoulou, Papadopoulou, Kaparounaki and Diakogiannis6} On the other hand, our results extend previous knowledge, as the group of university students who had self-injured only in childhood and adolescence also show a specific risk due to the amplification of perceived emotional burden and urge to self-injure. Despite cessation of self-injurious behaviour in the past, these students also represent a vulnerable group to potentially resume self-injurious behaviour.

Limitations of the study are a lack of generalisability to samples other than university students and the use of subjective ratings about self-perceived changes via online survey. Moreover, it should be emphasised that this study is not a longitudinal study, but an online survey in a cross-sectional design. For future research, conducting longitudinal studies would be important to examine causal relationships. In addition, other variables should be collected in the future to characterise the sample (e.g. ethnicity, refugee status and academic performance), which would allow analyses for subgroup differences.^{Reference Cipriano, Cella and Cotrufo2,Reference Kiekens, Claes, Demyttenaere, Auerbach, Green and Kessler10,Reference Verroken, Schotte, Derluyn and Baetens11} Strengths are the anonymity of participation and using an online survey to reach a wide range of affected university students studying various subjects during the COVID-19 pandemic.

Future studies should investigate relevant protective and risk factors for NSSI in university students during the pandemic. Results to date indicate that the reduction of social stress and more time for self-care resulting from the pandemic were particularly beneficial, whereas being alone, financial distress, severity of COVID-19 infection and experiencing increased stress are seen as major risk factors.^{Reference Lewis, Kenny, Pritchard, Labonte, Heath and Whitley12,Reference Oh, Marinovich, Jay, Marsh, Zhou and DeVylder13} With many restrictions and the loss of resources due to the pandemic (e.g. social distancing and isolation, elimination of leisure activities and online learning at home), it is important that university students at increased risk for self-injury be offered various prevention and intervention options through universities and colleges.^{Reference Hasking, Lewis, Bloom, Brausch, Kaess and Robinson14} These measures could include, for example, online support for students and their families as well as campaigns to strengthen the sense of community within the university.^{Reference Hasking, Lewis, Bloom, Brausch, Kaess and Robinson14} The use of screening procedures for important risk factors (e.g. financial problems, urge to self-injure, problematic alcohol use, experience of abuse, and depressive symptoms) by professional and trained health workers at universities would also be useful.^{Reference Hasking, Lewis, Bloom, Brausch, Kaess and Robinson14–Reference Paul and Fancourt16}