1. Introduction

Bullying happens quite frequently in nowadays culture, and bullying in schools is even more prevalent, with bullying becoming a global school problem. An overall agreement has arisen in which bullying is viewed as a type of forceful conduct. There is in which there is an irregularity of force leaning toward the perpetrator who more than once looks to hurt or threaten a designated person [1]. School bullying was first systematically studied by Olweus. According to him, bullying is the repeated and prolonged treatment of a particular student or group of students by a group or individual student, with some forms of negative action. School bullying involves victims, bullies, and bully-victims.

School bullying has a negative impact on students' emotional health as well as their physical health [2]. Depression is a major culprit in teen suicide, depression fundamentally intervened the connection between conventional bullying and self-destruction endeavors for the both females and males, with depression representing 42%-60% of fluctuation in self-destruction endeavors, separately. Therefore, it is important to reduce the risk of depression in adolescents due to bullying in schools. This article can not only enrich related research and provide a comprehensive grasping of why there is a connection among school violence and depression during adolescents, but also promote better advance of adolescents' health both physical and emotional through this relationship. Much of the previous research has emphasized the relationship between bullying and depression, bullying and suicide, and bullying and anxiety disorders. These studies have been relatively sparse in the areas of depression, suicide, and anxiety disorders as well as bullying, and the present study makes a synthesis of research on bullying and mental health issues. This study hopes to further help researchers go on to discover more useful preventative measures to mitigate the effects of bullying in schools on the mental health of adolescents by exploring the direct relationship between bullying behaviors and mental illness. Understanding the unique and overlapping effects that occur after going through different forms of bullying is important to guide interventions.

1.1. Definition of Mental Health

Mental health refers to a psychological state and a process that is well and sustained. This manifests itself in the vitality of an individual's life. This manifests itself in the vitality of an individual's life, established spiritual experience, well gregarious orientation, and the capacity to efficiently utilize one's material and spiritual possibility as well as one's active social functions as a participant in society. Mental health has at least two meanings: the absence of mental illness and positive psychological development. That is to say, mental health refers to both an efficient and satisfactory ongoing mental state and the integrity and coherence of the process of basic human mental activities, i.e., the integrity and coherence of knowledge, emotion, intention, behavior and personality, and the ability to adapt to society. Please remember that all the papers must be in English and without orthographic errors.

1.2. Definition of Depression

The Latin word 'deprimere', which means to press down, is where the word 'depression' comes from [2]. The term 'syndrome of melancholia' was used by Hippocrates, an ancient Greek physician, to describe the symptoms of illness that last for a long time. The concept was similar, but it was more expansive than today's depression. The manifestations of sadness, frustration, and depression were pointed out, frequently involving fear, anger, delusions, and obsessions. Depression comprises of a sickness with rotted temperament as its primary symptomatology. There are additionally agonizing sentiments, misery, propensity to segregation, demotivation, lack of care, abulia, trouble to appreciate, sadness, engine restraint, hypotonia and negative considerations, remembering potential illusions for instances of serious seriousness [2].

1.3. Definitions of Bully and Bullying

As per Merriam-Webster, bully was first authored in 1548 and implies one of four things: a blustering browbeating person, a hired ruffian, sweetheart and a fine chap. The first definition is currently generally utilized [1]. People usually think of bullies as one who is habitually cruel, annoying, or threatening to other people who are more fragile, more modest, or here and there powerless. During the 1980s, Olweus put forward the meaning of bullying: “The act of a student engaging in negative behaviors towards specific students for a prolonged period of time and repeatedly is considered bullying” [1]. Then he came up with a new definition back in 2010: physical contact, verbal or other means of producing negative behavior, such as making gestures with insults, humiliating the other person's size or appearance, or deliberately isolating the other person. In layman’s terms, bullying can be portrayed as people who have difficulty protecting themselves were injured by purposeful, rehashed, unpleasant or hurtful behavior by at least one individual. The most recent definition was proposed by Volk and colleagues [1]. This definition is unequivocally grounded envelops natural and transformative settings. "Bullying is forceful essive objective coordinated conduct that hurts one more person inside the setting of a power unevenness." Bullying can be subdivided into direct and indirect bullying behaviors, with the former including direct material bullying and direct oral bullying. Indirect bullying is bullying behavior that is carried out by the bully with the help of a third party. In other words, whether it is physical kicking and punching, verbal intimidation, relational ostracism, or physical or gender taunting, it can be considered as bullying.

2. The Effect of Bullying on Depressive Symptoms

According to research, depression is more likely to be experienced by those who are victims or perpetrators of bullying in different situation than by those who are just victims and perpetrators. A relationship guided by the pain of psychosocial working [3]. Bullying in schools exposes young people to negative evaluations and attacks, causing them to doubt and deny themselves. Those who are bullied often doubt their own value and ability and believe that they do not deserve respect and care. In the long run, this negative perception will have a distorting effect on the victim's personality, affecting their healthy growth and development. Bullies appear to use aggression as a strategy to control their peers or to achieve their goals, and bullies exhibit social cognitive biases that support aggressive behavior. Surprisingly, victims of bullying showed similar social cognitive biases. The relationship between depression and bullying can also work the other way around, meaning that depression may make teens more vulnerable to bullying, or teens with depression may perceive bullying as an unfair interaction. Ferraz de Camargo and Rice examined the correlation among three different forms of bullying victimization and depressive symptoms among adolescents [4]. The study comprised 12 to18-year-old teenagers who had experienced bullying over the previous school year and used questionnaires to measure depressive symptoms after the adolescents had experienced three types of bullying. The findings confirmed that bullying victimization has an ongoing detrimental effect on adolescents' mental health. In addition, of these types of bullying, relational bullying is harder to detect because often the bully will not be able to tell whether he or she is being bullied or is in conflict with a friend. In other words, implicit bullying is more likely to be misunderstood and distorted by depressed teens. In Ferraz de Camargo and Rice's study it was found that greater use of positive reappraisal can reduce depressive symptoms in victims of implicit bullying. The meaning of bullying can be redefined through the use of reappraisal. Resilience to depression can be enhanced by changing bullying from negative to more positive [4].

Suicide is a significant cause of death for adolescents, and the development of mental illness can result in suicidal thoughts. A study by Stewart and colleagues detected that bullying increases the risk of suicide in adolescents [5]. The study was conducted on adolescents who were admitted to the hospital for severe self-injury, failure of outpatient treatment, and active suicidal ideation, and who had received treatment for acute psychiatric disorders within 48 hours. The study showed that severity of depression was linked with various forms of bullying, suicidal ideation and formulation in the previous month, and non-suicidal and risky behaviors. Publicly victimized and reputationally victimized bullies were linked with greater involvement in perilous behaviors, and greater involvement in risky behaviors was also associated with frequent suicide attempts. Indeed, depression serves play a role between adolescent bullying and suicidal ideation. There is a curvilinear relationship between bullying and adolescent suicidal planning, with only victimization predicting increased severity of suicidal planning. In this study, the direct effect of public victimization and honor victimization on suicide attempts was found only for females, not males. This is because females are more sensitive to interpersonal relationships than boys, they are more concerned about how they are perceived by outsiders and possess more distress after a bad incident with a friend.

3. The Relationship between Anxiety and Bullying

The relationship between adolescents suffering from anxiety and bullying is important because anxiety disorders are one of the most prevalent psychiatric disturbances between adolescents. Each participant in the study by Isolan and co-worker completed an anxiety self-test along with a questionnaire about bullying behavior and its frequency [6]. According to the research study, those who are bullied are more likely to suffer from anxiety disorders than those who are not bullied. Bullying victims were also often found to be at the highest risk for anxiety. Victimization is seen as a significant source of interpersonal stress that leads to anxiety and distress. Moreover, anxiety makes adolescents appear more vulnerable to bullies. Adolescents with anxiety are more jittery and anxious around their peers, which further leads to deterioration of interpersonal relationships, making them possible targets for further victimization, and internalizing the problem as an antecedent to, and a consequence of, their exposure to bullying, which is a vicious circle [6].

The scale was conducted with Chinese high school students, and it was found that bullying victimization had a positive impact on social anxiety [7]. Adolescents who have been subjected to physical, verbal, and relational bullying may have their coping mechanisms overwhelmed by these traumatic encounters, leading to helplessness and anxiety. Relational bullying, in particular, may cause adolescents to avoid socialization. In the long term, this can result in a decrease in teens' sense of belongingness, which can result in their distrust of others and fear of socialization, which can lead to social anxiety. The role of shame and self-esteem in bullying victimization and social anxiety has been observed to be significant, with bullying victimization influencing social anxiety through shame and self-esteem. The experience of bullying victimization can be cumulatively damaging to the victim. The experience of repeated bullying causes victims to negatively attribute the bullying to their own fault, causing them to continually self-condemn and increase their sense of shame. Because the experience of being bullied causes them to fear negative judgments from others, they tend to develop emotions such as anxiety and present avoidant and withdrawn behaviors in social situations in order to avoid this negative experience. Low self-esteem victims of bullying have difficulty in exercising the protective role of self-esteem in socialization, and therefore are unable to effectively alleviate and get rid of their anxiety, thus triggering more severe social anxiety. People with high level of shame will feel bad about themselves, which exacerbates their belief that they are worthless and increases their sense of shame. The accumulation of long-term negative emotions due to the experience of bullying victimization can trigger negative self-perceptions, which can lower self-esteem. As a result, social anxiety in bullied individuals ultimately increases through low level of self-esteem [7].

A three-year study of students from Finland by Acquah and colleagues examined the associations between social, emotional loneliness, social anxiety and bullying in adolescents [8]. Path analyses showed that both social and emotional loneliness increased adolescents' experience of bullying, but social loneliness was more tightly linked with bullying than emotional loneliness in both the seventh and eighth grade cohorts. All aspects of adolescent mental health problems were significantly related to bullying. And adolescents' loneliness and social anxiety both increase with grade level. Because peer support is so important to adolescents, social isolation in early adolescents is associated with bullying behavior. Precisely because adolescents want to build close relationships with their peers, when they are harmed in the process of building friendships it can lead to emotional loneliness, which in turn triggers hurtful behaviors. Moreover, the absence of close peers may exacerbate bullying behavior. This means that adolescents with internalizing mental health issues face difficult relationships, which also contributes to greater vulnerability to bullying [8]. The support of friends is very important to adolescents in relation to their self-concept and well-being, and as a result they also invest more time and energy in spending time with their peers. Due to this that peer bullying can produce a range of internalized mental health problems for adolescents.

4. The Impact of Bullying on Externalizing Behaviors

Externalization problems that occur in adolescents include anti-social behaviors that violate moral and behavioral norms, such as truancy, theft, self-harm, and aggression. After committing bullying, bullies often develop bad qualities and habits such as violence, aggression and irresponsibility, and are unable to control their aggressiveness and impulsiveness, which in the long run can lead to rebellious behavior or criminal tendencies. Adolescent drug use is a very significant public health problem, and drug use often goes hand in hand with other addictive behaviors such as gambling. Studies have found that early experiences with bullying are a risk for engaging in addictive and risky behaviors later in life. And the risk factor for addictive behaviors has been identified as school bullying. Richard and co-workers collected questionnaires from over 6,000 high school students, this survey looked at the frequency of bullying victimization, addictive behaviors, and the existence of anxiety, depression, and externalizing puzzler among participants. Externalizing problems, depression, and anxiety symptoms were found to play a significant role in explaining the correlation between bullying victimization and addictive behaviors [9]. Anxiety symptoms are largely responsible for this. The transition from bullying to addictive behaviors was influenced by externalizing problems, which had a statistically significant indirect effect. Higher levels of externalizing problems were found in individuals who had a higher frequency of victimization, which was linked to their participation in more addictive behaviors. Victims had relatively higher levels of depression, which was also associated with more addictive behaviors. Bullied individuals are likely to engage in one or more addictive behaviors, including smoking, drinking, marijuana use, and gambling. Engaging in multiple addictive behaviors in the face of bullying may be a maladaptive approach. This all reflects the serious consequences of bullying for high school students [9].

The impact of class-level bullying on the relationship between victimization and externalizing was assessed in a study by Liu and colleagues [10]. They further examined the role of Chinese adolescents' adverse attributional deviation in bridging this relationship. The study found that bullying was more strongly associated with externalizing problems in a relatively healthy environment, meaning that bullied individuals in classes with low levels of bullying were more likely to present with externalizing problems compared to classes with high levels of bullying. The victim's hostile attribution bias is strengthened by lower bullying at the class level, which in turn is associated with externalizing problems. Since the majority of the class is not bullied and the victim are unable to compare themselves with others who have had the same experience as they have, a few victims might believe that they are being deliberately targeted, and they will tend to perceive behaviors of unknown intent as hostile. These biased perceptions can lead them to develop externalizing problems, such as some aggressive behaviors. Moreover, the bullying experiences of close peers of the victims may increase the link between victimization and aggressive behavior, but the victimization of non-intimate peers does not affect the link [10].

5. Conclusion

Violence correlations between the friend bunches in school lead to a consciousness of dejection in adolescents that, thusly, creates more prominent depressive symptoms. In addition, meta-examinations of many reports of longitudinal investigations also affirmed the lasting negative effects. The victims of chronic bullying were more likely to suffer from mental problems later in life than victims of occasional bullying. The impact of school bullying incidents experienced by students who play different roles in school bullying may be different. Involvement in bullying, negative coping styles and mental problem are closely linked. Negative coping styles lead to a higher risk of mental problems. Findings demonstrate that observing bullying particularly adds to nervousness and mental problems for adolescents. For bystanders who are also potential targets of bullying, mental problem might be especially high because of co-victimisation or re-victimisation experienced during the observation. Research has found that prosocial behaviors can reduce mental problems by relieving psychological stress in adolescents. Increased use of positive reappraisal can reduce depressive symptoms in victims of implicit bullying. The meaning of bullying can be redefined through the use of reappraisal.

The shortcomings of this study include the following aspects. First, only the short-term effects of bullying in schools on adolescent students were examined in most of the studies. Second, cyberbullying was categorized as indirect bullying, which is becoming more and more prevalent nowadays, and some research suggests that cyberbullying may be differently related to traditional bullying and mental issues. Further research is necessary to examine the various types of bullying that affect adolescent psychological issues. Finally, family functioning, childhood trauma, and family history of mental illness may influence mental health of adolescents, but previous studies did not consider whether these serve as covariants to bullying. Prosocial behavior contributes to overall well-being. Adolescents' participation in pro-social behaviors protects them from depressive symptoms and contributes to good mental health. Helping youth to adopt fewer negative coping responses through psychoeducation or other similar interventions can reduce their risk of developing depressive symptoms. Bullying behavior can be reduced by bullying intervention. Subsequent researchers can study how to protect mental health of adolescents by providing effective intervention programs.