Trends in non-suicidal self-injury among adolescents: A global cross-temporal meta-analysis, 2007–2023

Non-suicidal self-injury (NSSI) among adolescents severely jeopardizes their well-being and has emerged as a significant global public health challenge. However, research on the trends in NSSI among adolescents remains scarce. This study sought to uncover the evolving patterns in the severity of NSSI among adolescents and the factors that influence these patterns. The Deliberate Self-Harm Inventory was employed to measure the severity of NSSI among adolescents. Relevant studies were retrieved from both Chinese databases (CNKI, Wanfang, and VIP) and English databases (Web of Science, PubMed, Scopus, ProQuest, and Wiley). A total of 70 articles (71 studies; N = 96,382) were included in this review. The data spanned from 2007 to 2023. The analysis revealed the following: (1) Although the severity of NSSI showed a small to moderate upward trend from 2007 to 2023, this increase did not reach statistical significance. (2) No significant differences in trends were observed among Asia, Europe, and the America. (3) Adolescents with clinical samples exhibited a more pronounced upward trajectory in NSSI severity compared to those with non-clinical samples. (4) Social development indicators (GDP per capita, Human Development Index, and Internet penetration rate) and social well-being (happiness index) exhibited significant positive correlations with NSSI among adolescents. Conversely, lower social equity (higher Gini coefficient) was associated with reduced NSSI among adolescents. This study elucidated the changing trends in NSSI among adolescents and offered novel insights for the early prevention and individualized intervention of NSSI among adolescents.