Non-suicidal self-injury (NSSI) is an act of direct and intentional injury to bodily tissues that has no suicidal purpose and is not socially and culturally acceptable. It includes stabbing, burning, tearing, scratching, and other forms of self-injury [1, 2]and is characterized by repetitive, deliberate, and covert behavior [3, 4]. Non-suicidal self-injury has always been present, but it was not until the Diagnostic and Statistical Manual Fifth Edition that NSSI was incorporated into emerging, unclassified behaviors and patterns. In 2019, the China Health Commission, together with 12 government departments, also issued the Action Plan for the Mental Health of Children and Adolescents, putting adolescent mental health in a crucial position. Non-suicidal self-injury has attracted much attention in the field of mental health and clinical practice because of its universality and serious consequences [5, 6]. In recent years, the rate of non-suicidal self-injury behavior among college students has been increasing [7, 8]. Non-suicidal self-injury behaviors among college students not only directly harm their physical health, but affect their emotional, academic, and interpersonal relationships [9, 10]. They are associated with the development of negative emotions such as mobile phone addiction, anxiety and depression [11, 12], and is an important risk factor for predicting future suicidal behaviors [13, 14]. There are a large body of researches on the causes and interventions of non-suicidal self-injury in China, but little research on the cause of non-suicidal self-injury from the perspective of core personality. Therefore, it is very important to explore the effect of self-consistency congruence on non-suicidal self-injury among college students.
There are some researches on the relationship between self-consistency congruence and non-suicidal self-injury, but there is still a lack of systematic exploration on the mechanism of self-consistency congruence and non-suicidal self-injury in college students. Self-consistency congruence is a concept proposed by Rogers, which refers only to the internal unity and external coordination of the individual and is the core concept of his personality theory [15]. The individual will experience anxiety, tension, and entanglement if there is an excessive gap between the inner self and the outer experience, that is, a state of "disharmony" [16]. Rogers believed that self-disharmony will lead to various internal conflicts. It is an important cause of psychological disorders, which are often manifested as abnormal psychological processes or personality characteristics. So self-dissonance is a significant inducement of self-injury [17]. Studies have shown that while college students have better overall self-consistency congruence, more than 13% of them are still very discordant and should be taken seriously [18].
Therefore, we propose hypothesis 1:
H1: College students’ level of self-consistency congruence negatively predict non-suicidal self-injury.
Self-dissonance is based on cognitive control systems and focuses on internal-external, self-experience conflict [19]. Negative emotion, as a key factor in regulating cognitive control [20], is consistent with the degree of self-disharmony in connotation. Bianchi and Phillips found that mobile phone users exhibit behavioral characteristics of non-suicidal self-injury [21]. Therefore, introducing negative emotions and mobile phone addiction mediating variables and exploring their mediating pathways can better clarify how self-consistency congruence affects non-suicidal self-injury.
The Mediating Role of Negative Emotions
Negative affect (NA) refers to a subjective experience of being trapped in a low mood and unpleasant activation situation, involving a variety of upsetting emotions such as shame, anger, disgust, guilt, fear, depression, and anxiety [22, 23]. Given that the university stage is a period of rapid but imperfect self-awareness development, college students may encounter various self-discrepancy and inconsistent situations [24], which can lead to self-dissonance and negative emotions such as depression, anger, irritability, anxiety, fear, and interpersonal sensitivity [24, 25]. Therefore, higher levels of self-dissonance in college students may increase their likelihood of experiencing negative emotions [24], which, in turn, can worsen non-suicidal self-injury (NSSI) conditions [26].
Consistent with the general stress theory (GST) model [27], which proposes that stressors, negative emotions, and risky behaviors are interrelated, individuals may engage in risky behavior when they fail to value and cope with negative emotions effectively. This idea is supported by both emotional management theory and the Empirical Avoidance Model (EAM), which posit that individuals typically experience negative emotions before engaging in NSSI as a maladaptive strategy to alleviate distress [28, 29]. Moreover, empirical evidence suggests that negative emotions precede actual NSSI and that NSSI is often regarded as an inappropriate emotional regulation method to relieve negative emotions [30].
Therefore, we hypothesize that negative emotions mediate the effect of self-consistency congruence on NSSI among college students:
H2: Negative emotions play a mediating role in the effect among college students' self-consistency congruence on non-suicidal self-injury.
The Mediating Role of Mobile Phone Addiction
Mobile phone addiction refers to the excessive use of mobile phones to engage in internet-related activities, resulting in a strong desire and dependence on mobile phones and causing social and individual function impairments and withdrawal reactions [31]. College students have a high prevalence of mobile phone addiction [32–34]. Previous research has found a negative correlation between self-consistency congruence and mobile phone addiction among college students, indicating that those with high self-consistency congruence are less likely to be addicted to mobile phones [35, 36]. It is important to note that college students who are addicted to mobile phones may not necessarily enjoy using them, but rather use them as a means to temporarily escape from internal and external conflicts resulting from self-discordance [37]. However, this avoidance strategy exacerbates existing conflicts and negative emotions, creating a vicious cycle that fails to solve the problem. Additionally, high levels of mobile phone dependence may be associated with mental health problems [38], and addictive traits have been linked to higher rates of self-injury [39]. As a subtype of internet addiction, mobile phone addiction shares similar features and symptoms with other types of problematic network use [40, 41]. Furthermore, several studies have shown a correlation between problematic internet use and non-suicidal self-injury, with internet addiction predicting the occurrence of NSSI [42–44]. Based on these findings, we propose the following hypothesis:
H3: Mobile phone addiction mediates the relationship between self-consistency congruence and non-suicidal self-injury among college students.
Therefore, we propose the following intermediary model. (see Fig. 1)