Non-Suicidal Self-Injury (NSSI) refers to deliberate and direct acts of harming oneself without the intent to die, such as cutting wrists, scratching arms, punching walls, taking drugs to experience pain, or pulling out hair (1). Previous studies often considered NSSI as a symptom of borderline personality disorder. In the most recent version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V), it is suggested that NSSI should be classified as a separate condition. Its purpose is to relieve interpersonal difficulties, unwanted thoughts, and emotions, as well as the negative impact on life (1). Research has shown that NSSI often begins in early adolescence, peaks in mid-adolescence, and declines in late adolescence (2). NSSI has become a major mental health issue among adolescents worldwide. In the past two decades, the number of individuals engaging in this behavior is rapidly increasing globally, particularly among adolescents (3). According to a study carried out by the Centers for Disease Control and Prevention in the US with 64,671 teenagers from the community, the occurrence of NSSI among adolescents varies from 6.4% to 30.8% (4). Similarly, a survey of 12,068 community adolescents across 11 European countries found a lifetime prevalence of NSSI ranging from 17.1% to 38.6% (5). Additionally, a meta-analysis found that 22.0% of adolescents worldwide have engaged in NSSI at some point in their lives, with an annual prevalence of 23.2% (6). In Asian countries, the overall lifetime prevalence of NSSI is higher at 32.6% compared to Western countries at 19.4% (7). Although NSSI does not involve suicidal intent, it frequently happens alongside suicidal behavior and can be a significant indicator of future suicide attempts and completed suicides (8). A meta-analysis of longitudinal studies estimated that individuals engaging in NSSI are 4.27 times more likely to attempt suicide and 1.51 times more likely to die by suicide subsequently (9). According to interpersonal psychological theory and the three-step theory of suicide behavior, NSSI is considered a “gateway” behavior to suicide (10). Repeated NSSI may desensitize individuals to pain, injury, fear, and death, thereby increasing the likelihood of suicide attempts. Therefore, it is essential to assess the factors influencing NSSI to prevent suicidal thoughts and behaviors.

In recent times, with the widespread adoption of the internet, it has evolved into an essential tool for adolescents across various domains including education, social interaction, and recreational activities (11). According to the 49th Statistical Report on Internet Development in China published by the China Internet Network Information Center (CINIC), the number of internet users in China has surged to 1.03 billion, with adolescents constituting 137 million of this demographic, accounting for 13.3% of the total internet user base in the country (12). Despite the manifold benefits that the internet offers to adolescents in terms of learning and daily life, excessive and uncontrolled usage of this technology may lead to what is commonly referred to as “Problematic Internet Use (PIU).” (13–15). PIU is defined as internet usage that results in psychological, social, educational, and/or occupational difficulties in an individual’s life, which encompasses terms such as “pathological internet use”, “excessive internet use”, “internet dependency”, “excessive smartphone usage”, and “compulsive internet use.” (16). Research suggests that PIU among adolescents can result in a myriad of severe issues, including attention deficits (17), academic underachievement (18), interpersonal conflicts (19, 20), family discord (21), anxiety (22), depression (23), and even instances of NSSI (24).

Adolescent NSSI arises from a complex interplay of social, psychological, and environmental factors (25). Notably, a substantial correlation exists between adolescent NSSI and PIU (26), with certain studies suggesting that PIU serves as a predictor for NSSI occurrences (24). However, a study by Liu et al. discovered that, upon controlling for depression variables, the linkage between adolescent NSSI and PIU dissipated (27). This finding underscores the intricate and contentious nature of the relationship between adolescent NSSI and PIU, with variations in outcomes across different research endeavors. To date, five systematic reviews have delved into this correlation, with two being narrative reviews (28, 29). While these reviews hint at a connection, methodological limitations obscure the true nature and strength of this association. Similarly, a meta-analysis spanning multiple European and Asian nations suggests that, even after adjusting for potential confounders like depression, PIU retains a link with heightened suicidal tendencies, albeit without a detailed exploration of the relationship between NSSI and PIU (30). Moreover, previous investigations have failed to specifically hone in on adolescents as a distinct cohort. In two systematic reviews conducted in China, the association between adolescent NSSI and PIU emerged as particularly robust. Nevertheless, these reviews encompassed a mere 3 and 4 articles, respectively, without delving deeper into potential influencing factors. Hence, further research is imperative to enhance the robustness of these findings (26, 31). Consequently, this study aims to amalgamate prior research on the NSSI-PIU relationship among Chinese adolescents, while considering factors such as measurement tool diversity, study type disparities, sample demographics (age, gender, region), and the control of potential confounders like depression, which could impact the outcomes of meta-analysis (30). Such an endeavor seeks to furnish a framework for the development of more targeted intervention initiatives in the future.

In recent years, adolescent NSSI has emerged as a pressing global public health concern (58). Concurrently, PIU has garnered increasing attention as a significant contributing factor to problematic behaviors among youth (26). Despite extensive research efforts, a definitive consensus regarding the relationship between NSSI and PIU remains elusive (24, 27). The outcomes of this meta-analysis reveal a notable correlation between NSSI and PIU among Chinese adolescents, with those afflicted by PIU being over twice as likely to engage in NSSI compared to their non-PIU counterparts. This finding resonates with earlier research, including the study conducted by Fan et al. (26). The rationale behind this phenomenon can be dissected as follows: Firstly, a reciprocal interaction between NSSI and PIU may exist, wherein the internet serves as a platform for NSSI exposure. Adolescents immersed in PIU are more predisposed to encountering peers and information related to NSSI, thereby amplifying the likelihood of imitation and engagement in NSSI behaviors. Social reinforcement further accentuates the risk of NSSI occurrences, ultimately culminating in the manifestation of such behaviors (59). Secondly, both NSSI and PIU share addictive propensities (60, 61). The Interaction of Person-Affect-Cognition-Execution (I-PACE) model posits that addictive behaviors ensue from intricate interactions between susceptibility factors, emotional and cognitive responses to specific stimuli, and executive functions like inhibition control and decision-making. Throughout the addictive trajectory, the correlation between cue-reactivity/craving and diminished inhibition control fosters habitual behaviors (62). Research suggests that prolonged PIU may induce structural and functional alterations in the adolescent brain, particularly impacting areas pertinent to executive control and decision-making, thereby elevating the risk of NSSI (63–66). Additionally, sustained PIU could precipitate neuroadaptation alterations within the brain’s reward system. Moreover, addictive behaviors are associated with the release of hormones and neurotransmitters (e.g., endogenous opioids), potentially distorting individuals’ reward and punishment perceptions, consequently heightening their inclination towards NSSI (67, 68). Thirdly, PIU may engender social detachment from real-life interactions and undermine adolescents’ coping mechanisms for managing challenging emotions and sentiments. Adolescents engrossed in PIU may necessitate additional support and mechanisms to alleviate their psychological and emotional distress. The intense physiological sensations accompanying NSSI can serve as a diversion from internal psychological distress towards external physiological experiences, thereby instigating NSSI incidents (61, 69). Fourthly, PIU could precipitate personality disintegration, impairing adolescents’ typical social functioning and diminishing their vigilance and fear-related emotions. This often culminates in impulse inhibition disorders, thereby heightening the likelihood of NSSI occurrences (70). Lastly, adolescent PIU closely intertwines with mental health concerns such as anxiety and depression, both significant predictors of NSSI. PIU might initially function as a coping mechanism to alleviate mental health challenges; however, over time, it exacerbates these issues, thereby escalating the risk of NSSI (71, 72).

The study’s findings unveil a significant moderating impact of regional disparities on the relationship between NSSI and PIU. Notably, in China’s western region, adolescents grappling with PIU face a substantially heightened risk of NSSI, up to four times greater compared to several other regions in the country, with the lowest risk observed in the eastern region. This discrepancy may stem from the relatively underdeveloped economic status and prolonged parental absences due to occupational commitments prevalent in the western region. Such circumstances may foster an environment lacking in emotional communication within adolescents’ families, consequently elevating the risk of PIU and subsequent NSSI (73). Dysfunctional family dynamics, in turn, exacerbate the vulnerability to NSSI among adolescents (74). Thus, the association between NSSI and PIU appears more pronounced among adolescents in China’s western region, accentuating the imperative to fortify mental health intervention efforts targeted at this demographic.

Furthermore, the study reveals a significant moderation effect of age on the relationship between NSSI and PIU. Specifically, adolescents afflicted with PIU exhibit a heightened risk of NSSI compared to university students. This observation can be attributed to the pivotal stage of physiological and psychological development experienced by adolescents, characterized by nascent self-awareness, coping mechanisms, and social skills (75). In contrast, university students have transitioned into a more autonomous and mature phase of life. Owing to adolescents’ relatively weaker self-regulation and emotional control capabilities, they are more susceptible to the adverse effects of PIU, consequently escalating the risk of NSSI (76, 77). Additionally, adolescents are particularly influenced by peer dynamics and social networks, rendering them more susceptible to PIU. Conversely, university students may possess superior critical thinking and self-regulation abilities, which could mitigate PIU’s detrimental impact on their mental well-being, thus lowering the risk of NSSI (78, 79). Furthermore, adolescents often encounter barriers in accessing mental health resources and may feel disinclined to seek assistance due to familial, academic, and societal pressures (80). In contrast, university students typically have greater access to diverse mental health support systems and exhibit a greater willingness to seek aid, thereby reducing the likelihood of NSSI. This underscores the significance of addressing PIU concerns among adolescents and furnishing them with tailored support and intervention measures to mitigate NSSI occurrences.

Additionally, the study identifies a significant moderating influence of controlling for depression variables on the NSSI-PIU relationship. This implies that the heightened risk of NSSI among adolescents with PIU may be partially mediated by depression, although other contributing factors are also at play. This finding aligns with the conclusions drawn by Cheng et al. (30). One plausible explanation is that depression disorders are inherently intertwined with PIU; adolescents grappling with depression are more susceptible to PIU as a coping mechanism to alleviate psychological distress, with PIU potentially exacerbating depressive symptoms, thus perpetuating a detrimental cycle that heightens the risk of NSSI (81, 82). Moreover, adolescents contending with depression often grapple with heightened social isolation and a dearth of effective coping mechanisms, rendering them more susceptible to immersing themselves in the online realm, consequently elevating the risk of PIU and, by extension, the incidence of NSSI (83). Henceforth, it is advisable to screen adolescents with problematic Internet use for NSSI risk, even in the absence of depression, as additional factors may heighten NSSI susceptibility among individuals grappling with PIU.

Similarly, gender was identified as a significant moderator in the relationship between NSSI and PIU in this study. Findings indicate that among those afflicted with internet addiction, female adolescents are more predisposed to NSSI occurrences. This observation could be elucidated by several factors. Firstly, female adolescents tend to share personal experiences and emotions more openly on social media platforms, rendering them more susceptible to external judgments regarding their appearance, body image, and lifestyle choices. Such online interactions may exacerbate issues related to self-identity and self-doubt, thereby heightening the risk of NSSI subsequent to PIU engagement (84, 85). Secondly, female adolescents are more prone to internalizing problems such as depression and anxiety, while male adolescents are inclined towards externalizing problems such as aggression and behavioral issues. Among adolescents grappling with PIU, internalizing problems are more likely to manifest in females, consequently augmenting their NSSI vulnerability (86, 87). Thirdly, female adolescents typically rely more heavily on social support networks than males, and may lack effective self-regulation skills when confronted with stressors. This renders them more susceptible to immersing themselves in the online realm as a means of escaping real-life challenges, thereby escalating the risk of NSSI (88, 89). It’s important to note, however, that the subgroup analysis in this study comprised only two articles, potentially limiting the generalizability of the findings.

However, neither the assessment tools for PIU nor those for NSSI exhibited a moderating effect on the relationship between NSSI and PIU. This suggests a degree of stability and consistency in the outcomes derived from various assessment instruments. It should be noted that the inclusivity of PIU encompasses various terms and employs different measurement tools, which may limit the generalizability of research findings. Therefore, further exploration is needed to determine whether the relationship between PIU and NSSI is moderated by other measurement instruments. Lastly, different study methodologies also failed to moderate the relationship between NSSI and PIU, indicating that disparate study designs do not significantly influence the study outcomes.

The outcomes derived from this systematic review and meta-analysis undeniably underscore a robust and statistically significant positive correlation between NSSI and PIU among Chinese adolescents, affirming that adolescent PIU heightens the propensity for NSSI occurrence. Particular emphasis should be placed on specific demographic segments, including those situated in the western regions of China, middle school attendees, adolescents grappling with concurrent depressive disorders, and female adolescents, as they may confront elevated rates of PIU, consequently amplifying their vulnerability to NSSI risk. Thus, the imperative for early detection and targeted interventions for PIU adolescents cannot be overstated, directly mitigating the frequency of NSSI incidents. Adolescence represents a pivotal developmental phase marked by distinct psychological and physiological attributes, during which educational institutions and familial environments play pivotal roles in reinforcing adolescent mental health education. This entails heightening awareness surrounding PIU and NSSI while bolstering adolescents’ mental health literacy and resilience. Concurrently, addressing PIU concerns among adolescents necessitates the establishment of tailored intervention frameworks. Educational institutions can institute dedicated platforms or curricula geared towards the prevention and management of PIU, offering psychological counseling and support services. Psychologists and clinical practitioners can devise individualized treatment regimens tailored to specific circumstances, aiding adolescents in cultivating constructive coping mechanisms, alleviating psychological distress, and mitigating NSSI occurrences. Moreover, encouraging adolescents to actively engage in extracurricular pursuits such as sports, arts, and cultural activities can foster diverse interests and hobbies, thereby curtailing excessive internet utilization. Promoting a wholesome lifestyle encompassing sound sleep patterns, balanced nutrition, and moderate physical activity is also advocated to alleviate PIU and NSSI tendencies. By adopting a multifaceted approach encompassing early intervention, targeted support services, and lifestyle modifications, stakeholders can effectively address the intertwined challenges posed by PIU and NSSI among adolescents, safeguarding their overall well-being.

The original contributions presented in the study are included in the article/ Supplementary Material . Further inquiries can be directed to the corresponding authors.

XH: Validation, Software, Project administration, Methodology, Investigation, Formal analysis, Data curation, Conceptualization, Writing – review & editing, Writing – original draft. QY: Writing – original draft, Data curation. JP: Writing – review & editing, Supervision, Methodology. JY: Writing – review & editing, Software. TW: Writing – review & editing, Investigation. YQ: Writing – review & editing, Software. SW: Writing – review & editing, Methodology. TD: Writing – review & editing, Methodology. YL: Writing – original draft, Data curation. CH: Writing – review & editing, Investigation. PY: Writing – review & editing, Validation. BY: Writing – review & editing, Validation, Supervision.