Self-Harming Behavior in Adolescents: Current Diagnostic and Therapeutic Approaches

Abstract

Self-harming behavior (SHB) refers to a culturally disapproved situation in which a person intentionally damages his/her own body. SHB is an important public health problem in the world, especially during adolescence, and is widely encountered in clinical practice. It can be seen together with psychopathologies such as depression and borderline personality disorders, but it can also occur without concomitant psychopathology. In addition to the fact that SHB has a high risk of recurrence and can result in negative mental health problems in the long term, it is also one of the most important risk factors for suicidal behavior. Studies on SHB have increased in recent years. However, the epidemiology and etiology of SHB have not been fully elucidated. In addition, there is no psychotherapeutic intervention method or pharmacological agent whose effectiveness for SHB has been proven yet. In this article, it is aimed to review the studies related to the definition, epidemiology, risk factors, and treatment of self-harming behavior.

1. Introduction

Self-harming behavior (SHB) can be defined as all behaviors that result in a person intentionally injuring himself to some extent physically and psychologically or that are performed with the foresight of this type of result [1]. In both clinical and community samples, it is a common mental health problem among adolescents and young adults [2]. Although SHB has traditionally received less attention than suicidal behaviors, it is increasingly recognized as a prominent and important clinical phenomenon. SHB manifests itself widely in forms such as cutting, scratching, hitting, striking, carving, and scraping [3]. It is stated that SHB often serves functions such as reducing negative emotions, distracting, or punishing oneself [4]. SHB does not occur only in the context of psychiatric disorders, such as mood disorder, anxiety disorder, post-traumatic stress disorder, eating disorder, substance use disorder, and borderline personality disorder. It can also occur without a comorbid psychiatric diagnosis [5, 6]. It is reported that SHB often begins in early adolescence, reaches its peak in the middle of adolescence, and its frequency decreases toward late adolescence [7, 8]. Although there is a significant decrease in the frequency of SHB from late adolescence to early adulthood, the risks related to long-term mental health problems, suicidal tendencies, and risk-taking behaviors increase in individuals who have SHB repeatedly during their adolescent years. For this reason, prevention, diagnosis, and early intervention of SHB are important. In this article, it is aimed to review the causes and treatment of SHB in the light of current studies.

2. Definition and history of self-harming behavior

Self-harming behavior (SHB) is defined as a behavior of intentionally, directly harming a person’s own body without suicidal intent [1]. Throughout history, self-harming behavior has taken place in different sources. For example, the Bible tells the story of “a man who injured himself with stones while shouting and is under the rule of elves” [9, 10]. In the tragedy of King Oedipus in Greek mythology, it is told that King Oedipus removed his eyes in feelings of guilt and sinfulness when he found out that he had married his mother after killing his father [10, 11]. In Norwegian mythology, it is mentioned that Odin gave one of his eyes to be able to drink a single sip of the water of the Mimir’s Well to have wisdom and intelligence [11]. In the medical literature, on the other hand, it is first mentioned about a female patient who had removed her both eyes in feelings of guilt in 1946 [9, 11]. In early psychoanalytic studies, SHBs, which led to genital injuries and organ loss, were considered as behaviors performed to prevent fear of castration, masturbation, and deviant sexual desires. Emerson used the concept of self-mutilation for the first time in a study in which he evaluated cutting oneself as a symbolic view of masturbation [12]. In addition, in the 1930s, the psychoanalyst Karl Menninger expressed acts of self-harm as a kind of debilitated suicide, and he also used the term self-mutilation [13]. Especially in the early literature, all forms of non-fatal and intentional self-harm behaviors were considered suicide attempts, regardless of whether there was any suicidal intention in the expressed action. However, there were different opinions in this period [13]. In the 1960s, some authors stated that the vast majority of people who self-harmed did not attempt suicide [13]. In 1983, Pattison and Kahan mentioned that not all self-harming behaviors can be classified as suicide attempts, and they emphasized that a person can intentionally cause physical harm to himself even without suicidal thoughts [14]. In 1989, Favazza defined SHB as repetitive and non-life-threatening self-harming behavior [15].

A historical and current assessment of self-harming behavior was made by Favazza, and it was emphasized that self-harm and suicide were separate concepts [9]. However, Favazza also considered the cultural effects and divided the self-harming behavior into two: culturally approved self-harm and non-cultural (non-approved) self-harm [9]. The basic understanding today is that the goal of a person who attempts suicide is to put an end to all his feelings, but the goal of a person who harms himself is to try to feel better. However, it is stated that those who cut themselves repeatedly are at a high risk of suicide, and especially under the influence of drug overdose, the risk of death increases since they cannot control their self-harming behavior.

Since the date it was first expressed, SHB has been defined in different ways and different terms have been used to express it. Even when SHB is limited to non-suicidal behaviors, terms such as “parasuicide,” “self-injury,” “self-mutilation,” “delicate self-cutting syndrome,” and “considerate self-harm” or “non-fatal considerate self-harm” have been used to describe it [1, 13]. When looking at the studies conducted in recent years, it is seen that the research on self-harming behaviors is increasing, and more clear and consistent definitions and terms are used [1]. However, there is an ongoing debate on how to correctly define “self-harming behavior” internationally. In the international diagnostic classification, SHB did not have any category until the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, fifth edition) was created. In the DSM-4, it was expressed as repetitive and dysfunctional motor movements such as “self-biting, skinning, hitting the head, hitting the body enough to disrupt functioning or require treatment” in stereotypical behavior disorder, while it was expressed as “self-destructive behaviors” in borderline personality disorder [16]. In DSM-5, as a result of emerging ideas indicating that it is a different disorder, it was considered as a separate clinical condition that would guide future studies. DSM-5 includes SHB as a new diagnostic category in the form of “self-harming history” under the heading of other situations where there is a personal history. In the criteria determined by DSM-5, SHB is defined as intentional harm to one’s own body in a socially disapproved or non-destructive manner. The importance of distinguishing it from overdose drug usage, culturally approved behaviors (e.g., piercings), and stereotypical forms recurring among people with developmental disorders is emphasized. As another criterion, it is recommended that self-harming actions should have taken place on at least 5 days within the last year. Moreover, DSM-5 underlines the non-adaptive “coping strategy” nature of SHB, and it is emphasized that the individual should have the goal of achieving a better emotional state after this action (self-harming). SHB was included in the DSM-5 as a disorder that needs more research as a different syndrome [17]. With the update of the DSM-5, intentional damage to the body surface without suicidal intent has been defined as “non-suicidal self-injury (NSSI),” and it is stated that distinction of it from a suicide attempt is still controversial [18]. In definitions (especially with the NSSI definition), it is emphasized that self-harming behavior can be distinguished from a suicide attempt, in which death is consciously intended. However, some studies have reported that although it is different from a suicide attempt, 50–75% of individuals with a history of SHB have attempted suicide [19, 20]. This situation causes controversy in terms of naming SHB as “non-suicidal self-injury.” While SHB includes both acts with or without suicidal intent, the term “non-suicidal self-injury” describes the intentional and direct destruction or alteration of body tissue in a way that is not socially accepted and takes place without suicidal intent, and therefore this term excludes suicide attempts [17, 21]. Although the intention behind the act of self-harming is clinically extremely important for risk assessment, the lack of empirical evidence supporting a clear distinction between self-harming with and without suicidal intent is highlighted [22]. A systematic review comparing studies using the definition of SHB with studies using the definition of NSSI suggested that there were no significant differences in the average lifetime prevalence rates and that this distinction was not obvious in the adolescent community sample [7]. In the literature, studies conducted in European countries and Australia predominantly use the term “deliberate self-harm” as a more comprehensive term for the harmful behavior of a person toward himself, regardless of suicidal intent [7, 8, 23]. In contrast, studies conducted in Canada and the United States use the term “non-suicidal self-injury,” which includes only directly harmful behaviors without suicidal intent [7, 8, 23]. In this article, the term “self-harming behavior” is used to express this situation.

3. Epidemiology

In the literature, highly variable rates of SHB prevalence are reported. Since the day of its identification, it has been stated that different definitions of self-harming behavior may cause inconsistency in the data obtained in epidemiological studies. In a systematic review of 35 articles related to SHB, it was stated that 11 different terms had been used to describe self-harming behavior, and 20 different methods had been used to measure it [24]. In the study, it was reported that definitions were particularly problematic since the distinction between suicidal and non-suicidal behaviors was not clear. In the review, it was revealed that the authors who explained these semantic differences had reported SHB prevalence rates ranging from 2.9 to 41.9% in normal populations and from 13 to 59% in clinical populations [24]. As a result of a systematic review and meta-analysis of studies conducted with nonclinical sample groups, the prevalence of SHB was reported as 17.2% in adolescents, 13.4% in young adults, and 5.5% in adults [25]. In addition, in a recent meta-analysis study involving 66 studies consisting of 686,672 children and adolescents, self-harming behavior was considered separately as NSSI and deliberate self-harm, and lifetime prevalence and 12-month prevalence were calculated. The rates were reported as 22.1 and 19.5% for NSSI, 13.7 and 14.2% for deliberate self-harm, respectively [26]. In a meta-analysis study conducted between 1990 and 2015 with 597,548 participants aged 12–18 from 41 countries, the lifetime prevalence of SHB was reported to be 16.9% (Range: 4.1–39.3%), and it was stated that the rate had increased by 2015 [27]. In contrast to these results, the prevalence of SHB was found to be lower in a sample of adolescents examined based on the criteria recommended by DSM-5, and an approximate rate between 1.5 and 6.7% was reported [28]. In a recent study conducted with 1059 primary school children (8–9 years old) by applying a 4-year follow-up process, the 12-month prevalence of SHB was found to be 3% [29]. In another study, prevalence rates ranging from 55 to 68% were reported for patients admitted to psychiatric services [30]. In the literature, it is reported that SHB is more common during adolescence and young adulthood, and this behavior mostly begins at the age of 12–14 [2, 7, 8]. However, SHB has also been reported in younger children [31]. In a study conducted by Barrocas et al., self-harming behavior was observed in 53% of the 665 children included in the study, and this rate was reported as 7.6% in 3rd grade students, 4.0% in 6th grade students, and 12.7% in 9th grade students [31]. In a study conducted with 11,814 children aged 9–10 years in the United States, the rate for SHB was reported as 9.1% [32]. In another study conducted with a preschool clinical sample group, self-harming behavior was reported as 21.3% in children between the ages of 3 and 6 [33]. Looking at the difference between the genders, the first multicenter study conducted with more than 30,000 children and adolescents in 2008 revealed that the incidence of SHB in the last year was 8.9% in girls and 2.6% in boys [34]. In many studies conducted in later years, it has been reported that SHB is more common in girls than in boys [35, 36]. However, there are also studies reporting that SHB is observed in equal proportions in females and males [37, 38, 39].

4. Etiology and risk factors

Many studies have been conducted on the causes of SHB in adolescents, and it has been emphasized that many factors (e.g., genetic, biological, psychological, physiological, social, and cultural) play a role [3].

4.1 Neurobiological factors

Research focusing on the development and continuation of self-destructive behaviors as well as neurobiological factors has been mostly conducted with adults with borderline personality disorder [6]. However, in recent years, there has been an increasing focus on neurobiological changes in adolescents participating in NSSI. In an imaging study conducted with adolescents, it was determined that SHB was associated with a decrease in the volume of gray matter in the insula and anterior cingulate cortex [40]. In a functional MRI (fMRI) study focusing on adolescents with SHB, it was reported that significantly higher responses were observed in the bilateral amygdala, hippocampus, and anterior cingulate cortex when processing emotional stimuli compared to healthy control group and depression explained this difference; in addition, it was shown that increased activity in the amygdala and anterior cingulate cortex was more in response to negative, positive, and neutral pictures in adolescents with SHB compared to healthy controls [41]. In another FMR study focusing on depressed adolescents with SHB and a control group, social stress was applied to participants. Greater activation increases were reported in the medial prefrontal cortex and ventrolateral prefrontal cortices of depressed adolescents with SHB compared to depressed adolescents only and healthy control groups. The results indicated that social exclusion might process differently in depressed adolescents with SHB in brain regions related to the processing of previous social exclusion compared to adolescents with depression only [42]. In an fMRI study conducted with female adolescents, functional connectivity measurements of the amygdala during the task and at rest were performed, and it was found that adolescents with SHB showed atypical amygdala-frontal connectivity compared to the control group. It was revealed that there was a higher functional connection between the right amygdala and the dorsal anterior cingulate cortex and the supplementary motor area (SMA) [43]. A similar study focusing on the rest state also showed decreased amygdala activation between the anterior cingulate cortex, subcallosal cortex, paracingulate gyrus, right planum temporale, and right insula in adolescents with SHB compared to the healthy control group [44].

Considering the relationship of SHB with stressful situations, the relationship between SHB, the autonomic nervous system (OSS), and the hypothalamic-pituitary-adrenal (HPA) axis, which play a role in coping with stressful situations, was examined. OSS activity in SHB is studied by psychophysiological methods used in cardiac activities [45]. In the first study conducted with adolescents with SHB, parasympathetic activity-mediated heart rate variability (indicating the balance of sympathetic and parasympathetic activity) was examined, and it was reported that parasympathetic activity decreased at rest compared to the control group, and the parasympathetic response was lower when the negative mood was triggered [46]. A study found that there was no change in heart rate during stress induction [47]. In another study, it was reported that there was no difference in both heart rate and heart rate variability in adolescents with SHB compared to the control group [48]. In studies focusing on adolescents with SHB, it is reported that the HPA axis is affected [6]. In a study conducted by measuring saliva and hair cortisol in adolescents, it was reported that while there were no differences in hair cortisol compared to the control group, the cortisol wake-up response was higher in adolescents with SHB [49]. Another study conducted with siblings found that salivary cortisol levels in the SHB group decreased significantly after a trauma interview, while hair cortisol levels in the SHB group were significantly higher than in those without SHB [50]. Another study conducted on adolescents found that cortisol levels decreased in individuals with SHB in response to the Trier social stress test, and it was reported that this might indicate hyposensitivity of the HPA axis in adolescents with SHB in acute stress situations [6, 47]. Another recent study found that after social stress, depressed adolescents with SHB had lower corticol levels compared to adolescents with only depression and the control groups [51]. In some studies, increased HPA axle activation has been reported after cold pain stimulation in individuals with SHB [52]. A recent study also found no statistically significant difference in terms of blood cortisol levels between individuals with and without SHB [53]. A study examining the relationship of the stress response with SHB found that stress hormones (cortisol and dehydroepiandrosterone) had a relationship with factors supporting and maintaining SHB [54].

Very little is known about the genetic factors that affect the development of SHB. Gene-environment interaction was shown in a study conducted with adolescents to investigate genetic factors in SHB. In this study, it was shown in two independent samples that the SLC6A4 gene encoding the serotonin transporter and the carrier-dependent polymorphism region (5-HTTLPR) increased the likelihood of SHB in adolescents who had at least one short allele and were exposed to stress [55]. In a community sample study conducted with Chinese male adolescents, an interaction between variants of the Monoamine Oxidase A (MAO-A) and Catechol-O-methyl transferase (COMT) genes and experiences of childhood abuse was found in the prediction of SHB. However, in a carrier subgroup with the MAO-A T allele and COMT Met allele, there was no significant relationship between abuse experiences and the development of SHB [56].

It has been found that adolescents with SHB are more physiologically stimulated, their physical responses to emotional events are more severe, and their stress resistance ability is less [57]. In addition, it is reported that the pain threshold is high in these adolescents, and therefore, their tolerance to pain is greater [58]. However, regarding the perception and processing of pain in individuals with SHB, there are differences in the results obtained from adolescent samples. In a study comparing individuals with SHB with the non-SHB group, no differentiation was shown between the groups in terms of pain processing, but more activation in reward/pain and addiction-related regions was reported in fMR results [59]. In a follow-up study conducted on pain sensitivity in adolescents, it was stated that a decrease in the frequency of SHB after 1 year is associated with increased pain tolerance, which might lead to getting rid of SHB [60]. At the biological level, the findings indicating that the perception of pain is reduced in people with SHB have led to suggestions of endogenous opioid involvement. In studies conducted on adults, it has been shown that endogenous opioids are lower in individuals with SHB [61]. A recent study conducted with adolescents similarly found low beta-endorphin levels in individuals with SHB [62].

4.2 Demographic factors

In the literature, as mentioned above, it is reported that SHB often occurs during adolescence period, is most often seen during adolescence, and often decreases after young adulthood [1, 8, 35]. It has been stated that the developmental characteristics of adolescence may be a factor in an increase in the risk for SHB [63]. It has been reported that adolescence may be a factor in SHB both because it is a period when risky behaviors are frequent and because it is a period that is fragile from a neurodevelopmental point of view [3, 63, 64]. In meta-analysis studies, it is reported that in addition to age, gender (female) is also a risk factor for SHB in both adolescent and adult age groups [8, 35, 65]. It has been determined that the difference between females and males is higher in clinical populations, while this difference decreases in studies conducted with community samples [3, 35]. It has also been reported that the method used for SHB differs between females and males; the cutting-oneself method is more common in females, while methods such as punching a wall and head-butting a wall are more common in males [31, 66].

4.3 Socioeconomic level

It has been reported that low socioeconomic level, low level of education, and lower income and poverty are risk factors for self-harming [7, 31, 67, 68, 69]. It is stated that low income can be considered as a source of stress that can affect a child’s social-emotional, behavioral, and cognitive development [70, 71]. In addition, studies also report that low socioeconomic level is associated with the development and maintenance of self-harming [72].

4.4 Social and environmental factors

4.4.1 Peer bullying

In a 2.5-year follow-up study conducted by Hankin et al. [73], it was shown that dysfunctional relationships were a risk factor for SHB [73]. In the same study, it was also emphasized that peer bullying is a risk factor for SHB and SHB recurrence [73]. A study conducted with two large longitudinal sample groups (Avon Longitudinal Study of Parents and Children in the UK (ALSPAC) and Great Smoky Mountains Study in the US (GSMS)) found that exposure to peer bullying in childhood and early adolescence was associated with SHB at a higher rate during young adulthood compared to exposure to maltreatment by parents [74]. Another study involving 11 European countries (n = 12,098 adolescents) also showed that bullying was highly associated with self-harming behavior [75]. In a recent prospective study conducted with elementary school children, it was reported that the risk of SHB increased by 7 and 24 times, respectively, in 11- and 12-year-old children who had few friends and were exposed to peer bullying [29]. Also, in the same study, it was reported that peer relationships are strongly associated with self-harming behavior among elementary school children [29]. A multicenter 12-month follow-up study conducted in Europe in 2020 reported that being bullied was associated with the onset of SHB [76]. A meta-analysis study investigating bullying and including 156,284 adolescents aged 11–14 revealed that bullying and cyberbullying victimization were associated with SHB [77]. In a recent meta-analysis study on risk factors, the heterogeneity of the reviewed studies related to traditional and cyber bullying was emphasized and it was indicated it is a weak risk factor [78].

4.4.2 Social modeling

In the results of a review conducted on the relationship of SHB with social modeling, the effects of being affected by social contagion were shown, especially in the first self-harming behavior [79]. However, emphasis was placed on the fact that some of the studies had been carried out many years ago and they had methodological defects [79]. It has been reported that in line with social effects, identification with a certain youth subculture (gothic) increases the risk of SHB [80, 81]. It has been stated that young people in the subculture have both more frequent SHB and have stronger motivations, in addition, this situation cannot be explained solely by peer influence, the temperament and personality characteristics of the young person in the subculture (e.g., more introverted temperament, and being young people who engage in impulsive and risky behaviors more often) may contribute to this relationship [80]. However, there are also authors who defend that the increase in risk for the current condition can be explained not by subculture but by peer contagion [82].

In connection with a person’s internalized identity, societal norms, and societal values, his or her sexual orientation has also been shown to be a strong risk factor for SHB in many studies. It has been reported in many studies that young people who have sexual minority orientation or identify themselves as LGBT are at greater risk of SHB compared to young people who identify themselves as heterosexual [83, 84, 85].

4.4.3 Media effect

Regarding the worldwide spread of SHB, the use of the Internet and the use of social media are of interest. The Internet is seen as an applicable tool for individuals with a history of SHB in terms of sharing their life experiences and exchanging information among themselves [85]. In studies, it has been shown that adolescents with a history of SHB use the Internet more compared to those who do not have SHB history [86, 87]. A study conducted by Lewis et al. in 2014 found that terms related to SHB had been searched more than 42 million times in 1 year [88]. In the study, it was reported that 21.5% of the searched websites were health information websites, and only 9.6% of them were approved by a health or academic board [88]. Frequent searching of terms related to SHB on social media, watching videos containing SHB methods, and looking at their images have been reported to have some benefits in addition to some risks [85, 89, 90]. The most frequently mentioned benefit is to reduce social isolation. In addition, the fact that it may increase the incentive to heal, create an environment for emotional self-disclosure, and be a tool for resisting impulses have been mentioned among other benefits of it. Some issues such as the fact that it can contribute to the normalization of SHB behavior, cause the self-harming individual to internalization this identity, may increase competition through sharing, can increase the frequency and severity of SHB, can be a tool for learning new strategies, and it can also prevent recovery due to the fact that the presented emotions contain more negative elements have been reported among the risks of it [85].

4.4.4 Family characteristics and negative life events

Exposure to adverse life events is an important factor associated with SHB [91, 92]. In the literature, it has been stated that negative family emotions and negative family relationships are more frequent in adolescents with SHB [72, 93]. A 12-month follow-up study conducted with 1973 adolescents found that decreased family support predicts the continuation of self-injury, while increased family support is an important protector in terms of SHB [94]. In addition, it has been reported that adolescents who self-harm often find the family environment to be judgmental, emotionally stuffy, exclusionary, and insufficient in terms of support and care [72]. Also, in a different study, it was found that adolescents with SHB had more limited family communication, did not seek help, and could not cope with their problems, and because of this, they resorted to this method [95]. In a recent meta-analysis study on risk factors, low social support, parental substance abuse, criminalized past, history of sexual abuse, lack of religious or spiritual ties, psychological functioning of the family, and friends who had attempted suicide were considered among the risk factors associated with SHB [78]. In a cohort study, it was also reported that there was a positive linear relationship between adverse living conditions and the risk of self-injury at the age of 16 [96]. Exposure to maltreatment in childhood (emotional, physical, and sexual abuse, as well as physical and emotional neglect) has been identified as a risk factor for SHB in the literature [97, 98, 99]. However, in recent studies, different relationships between subtypes of childhood maltreatment and SHB have been reported. While a direct relationship between emotional abuse and SHB has been reported, it has been reported that sexual and physical abuse, difficulties in expressing emotions, and difficulties in the ability to cope with negative emotions mediate this relationship [100]. In a meta-analysis study involving 45 studies, it was reported that there was a weak relationship between childhood sexual abuse and SHB [101]. In studies conducted in later years, it has been reported that the relationship between SHB and sexual abuse is mediated by factors such as low self-esteem, dissociation, alexithymia, self-criticism, and post-traumatic stress [102]. Another study found that compared to physical and sexual abuse, children whose basic physical needs are not met may face a higher risk of self-harm [103]. Exposure to negative, stressful events in childhood and adolescence, and their repetition can lead to a deviation of the developmental trajectory, an increase in the formation of emotional symptoms (difficulties in mood regulation and an increase in depressive symptoms) and affect cognitive development and the formation of personality traits [104]. In terms of biological mechanisms, it has been reported that negative life experiences may have a negative impact on brain structural changes through the HPA axis and inflammatory cytokines [105].

4.5 Individual psychological factors

Difficulties in emotion regulation are reported as the main causes of SHB in 65–80% of adolescents with a history of SHB [106]. It is stated that emotional dysregulation is high in individuals with SHB and that SHB plays a role in improving this mood and regulating emotions [36]. In a study examining the relationship between emotional dysregulation and the onset of self-harm in adolescents aged 14–15 years, it was reported that before the onset of the first self-harm, participants experienced difficulties regulating their emotions and, in particular, deficits in expressing their emotions and poor impulse control [107]. In a meta-analysis study that reviewed 48 studies examining the relationship between SHB and emotional dysregulation, it was stated that emotional dysregulation is associated with a higher risk for SHB regardless of age or gender [108]. In a meta-analysis study conducted on longitudinal risk factors for SHB, it was found that emotional dysregulation was an important but weak predictor for SHB [36]. Recently, in a study that evaluated whether emotional reactivity and inhibitory control difficulties were experienced in adolescents in response to positive and negative emotions with a two-stage laboratory task, it was shown that adolescents with SHB decreased emotional sensitivity and showed lower levels of inhibitory control in response to images depicting negative emotional content; but these results were not determined in images depicting positive emotional content [109]. In addition, in the study, a relationship was found between emotional inhibitory control problems and the severity of SHB [109].

In the Biosocial Model proposed to explain borderline personality disorder, it is assumed that impulsivity, emotional vulnerability, resulting in emotional dysregulation, and interacting with an invalidating environment due to a biological predisposition can lead to SHB in young people [110, 111]. It is stated that an invalidating environment emerges in situations where emotional needs are not met appropriately, as well as it emerges in families exhibiting maltreatment. This theoretical model coincides with the literature that reveals that maltreatment in childhood can often lead to bad consequences, including emotional dysregulation and SHB [99, 100, 112].

Current approaches to SHB integrate emotional processing and social-cognitive theory to explain why some individuals are more likely to self-harm than others [113, 114]. According to the Cognitive-Emotional Model of SHB, being highly reactive to negative emotions is the mechanism by which individuals learn SHB is an effective strategy for regulating these emotions when they experience difficulties in regulating these emotions (e.g., they perceive that they have several strategies for dealing with their emotions). Conversely, it has been stated that individuals who believe that they can tolerate distress, resist the urge to self-harm, and use different strategies to manage their emotions will be less likely to self-harm [113]. According to the Benefits and Barriers Model, individuals who see themselves positively and perceive SHB as a painful, useless, and inhibitory behavior are less likely to see SHB as a useful way to cope with negative emotions. Therefore, they are also less likely to self-harm. In contrast, it has been stated that individuals who criticize themselves for not meeting high standards and experiencing low self-esteem are more likely to self-harm [114]. In accordance with this, it has been reported in the literature that individuals with a history of SHB have higher negative and lower positive characteristics, more emotional reactivity, psychological distress, difficulties in managing negative emotions, and negative schemas [108, 115, 116, 117, 118].

4.6 Recurring self-harming behavior

The recurrence risk of SHB is quite high. In review and meta-analysis studies, it has been reported that the most important risk factor for SHB is previous SHB [8, 36]. In addition, it is reported that psychiatric diagnosis is more common in adolescents with a history of recurrent SHB [8]. In a meta-analysis study in which 177 articles were reviewed, the recurrence risk of SHB was reported as 16.3% within 1 year and 22.4% within 5 years [119]. It has been stated that individuals who receive psychosocial support have an 18% reduced recurrence risk of SHB within 1 year [120]. A follow-up study conducted with a community sample found that 6.2% of young people aged 15–16 had self-harmed for 6 months, 2.6% of this rate had self-harmed for the first time and 3.6% had a repeated episode [121]. In addition, in a study in which SHB and suicide attempts were investigated in those with a history of SHB, it was found that the frequency of SHB predicts suicide [114].

5. Functions of self-harming behavior

Although various mechanisms related to the function of SHB have been proposed historically, the function of emotion regulation is one of the functions that receive the strongest empirical support [122]. It is stated that SHB is associated with decreases in negative emotions such as tension, fear, and sadness [122]. It is reported that although SHB is primarily considered as a way to reduce the negative effect, it also produces a positive effect, and the increased positive effect following SHB is associated with the recurrence of the behavior [122]. Nock and Prinstein proposed a four-function model approach related to behavior for the functions of SHB [1]. This approach suggests that behavior is caused by events that precede and follow it, and there are four possible reinforcement mediations of self-harm. The reinforcers that can support SHB both positively and negatively, as well as the personal (automatic) consequences of SHB in addition to the interpersonal (social) consequences are also described. For example, as an automatic negative reinforcement, SHB serves the function of reducing negative emotions or thoughts and helping a person to regulate their internal state (e.g., relieving tension, reducing feelings of anger), while as an automatic positive reinforcement, it allows a person to achieve pleasant or positive emotions or thoughts during or after SHB (feeling alive). Social positive reinforcement helps to reinforce social interaction (getting attention or sending messages to others), while social negative reinforcement helps to avoid unpleasant social interactions (e.g., parents stopping arguing, stopping peer bullying, not attending sports classes) [1]. This four-function model helps to organize and understand the definitions of self-harming behavior, and is supported by personal notification, behavioral and physiological data collected from various studies, examples, and contexts [1]. In the first clinical descriptions of self-harming, the stress-reducing features of this behavior were described in detail. In some cases, self-harming behavior has been defined as a means of signaling a person’s need for help or support [1, 14, 15]. Similarly, in more recent studies, the functions of self-harming behavior have been examined both in clinician interviews and in self-report scales, and it has been clearly shown that the results are consistent with the four-function model [1, 21, 123, 124].

6. Self-harming behavior as independent diagnosis

Although SHB has traditionally received less attention than suicidal behaviors, it is increasingly recognized as an important clinical phenomenon. It is mentioned that for a behavior to be classified as SHB, there must be will and intention (according to both the definition of Favazza and the DSM-5 diagnostic criteria). Accidentally cutting yourself is not SHB. However, in some cases, it can be difficult to determine the role of intentionality. For example, SHB can sometimes occur during dissociative episodes [125]. If a person engages in SHB when he/she is detached from reality, can SHB be considered intentional? In similar situations, if the motivation for self-harming is to feel something, then perhaps a degree of intentionality can be assumed. However, the example of self-harm occurring in the context of dissociation highlights the importance of developing a clearer definition for intentionality to the extent that this is possible [13]. Although there have been numerous studies about the nature of the relationship between SHB and suicide, there is still debate about this relationship. Although both SHB and suicidal behavior are forms of self-harming behaviors, it has been stated that there are some differences between them, such as intention, severity, and frequency [126, 127, 128]. It is mentioned that the most basic difference between SHB and suicidal behavior is related to the person’s intention [1, 128]. It is also stated, unlike suicidal behavior, in the SHB, the individual does not intend to end his own life and cannot perceive that his behavior will result in death [20, 128]. Although both behaviors involve avoidance of distressing emotional situations, suicidal behavior, unlike SHB, has the intention of ending one’s life [128]. Another difference between these two behaviors is caused by the methods used. It is stated that SHB usually involves methods with a lower risk of death (e.g., cutting, burning, biting), while suicidal behavior involves methods with a higher risk of death (e.g., overdose, wrist cutting, hanging) [1, 20, 128]. Another difference is related to the incidence; SHB is reported to be more common in both clinical samples and community-based studies compared to suicidal behavior [128]. In addition to the important differences between SHB and suicidal behavior, many findings have been obtained in the studies on the relationship of these behaviors to each other, and it is stated that these two disorders cannot be considered separate from each other [128]. Although the lack of suicidal intent was emphasized when defining SHD, it has been reported that in adolescents, SHD is often accompanied by suicidal thoughts, and this is an important risk factor for later suicidal thoughts and attempts [129, 130]. In studies, it has been shown that SHB is associated with suicidal behavior and is an important predictor of both recurrent SHB and suicide attempt [126, 131, 132, 133, 134, 135, 136, 137]. It has been reported that both the onset and recurrence of SHB during adolescence predict suicidal thoughts and behavior in late adolescence [138]. Moreover, any self-harm in adolescence has been associated with higher mortality and an increased risk of suicide even after 15 years [139, 140]. In addition, it has been stated in studies that both SHB and suicide can be seen simultaneously in most adolescents [141]. It is stated that many of the adolescents with SHB have also attempted suicide [19]. SHB has been reported as an important predictor of suicide attempt in young people with depressive disorder [131, 134]. In a meta-analysis of longitudinal follow-up studies, it was reported that people with SHB had 4.27 times increased risk of later suicide attempts and 1.51 times increased risk of death by suicide, regardless of suicidal intent [142].

7. Assessment tools

When assessing adolescents with SHB, a physical examination should be performed, it should be determined whether there is a priority need for emergency or surgical intervention, and the severity and frequency of SHB should be assessed [143]. It is recommended to discuss SHB separately with the teenager and family and to take a detailed history about it. Taking comorbid mental disorders into account, a complete mental state examination should be performed [143]. In addition, the risk of recurrence of SHB and the risk of suicide should be assessed during the SHB examination. During the interview, validity and reliability assessment tools are used to evaluate the SHB. Some scales that can be used in adolescents are deliberate self-harm inventory [37], functional assessment of self-mutilation [144], inventory of statements about self-injury [145], self-harm behavior questionnaire [146], self-injurious thoughts and behavior interviews [147]. However, the use of risk assessment tools and scales to predict future suicide or recurrence of self-harm is not recommended by the NICE (National Institute of Health and Clinical Excellence) guidelines [148].

8. Treatment approaches

There is no treatment that is considered the gold standard for SHB in children and adolescents [143]. Evaluation of the patient in different etiological dimensions and determination of additional psychiatric diagnoses are considered important in terms of the treatment process [149]. Individual psychotherapies, including cognitive-behavioral therapy and dialectical behavioral therapies, and psychopharmacological agents such as selective serotonin reuptake inhibitors (SSRIs) may be preferred based on the relevant psychopathology [150]. In this section, information obtained from studies on psychotherapeutic interventions and pharmacological agents is presented.

8.1 Psychotherapeutic interventions

Psychotherapeutic interventions for SHD in children and adolescents include a wide range of therapeutic approaches and orientations, including cognitive-behavioral therapies (CBT), dialectical behavioral therapy (DBT), interpersonal therapy, psychodynamic therapies, family therapies, and parent education interventions [151]. In review and meta-analysis studies, the evidence of effective psychosocial treatment interventions for SHB has been evaluated. It has been stated that the meta-analysis studies focused on psychotherapeutic approaches as well as pharmacological treatments and showed the clinical effects of interventions such as DBT and CBT, but the results obtained were insufficient to determine the treatment protocol [150, 151]. A review of 11 studies conducted in 2015 highlighted the lack of evidence level, and there was little evidence to support the effectiveness of group therapy, while mentalization-based therapy (MBT) and DBT were indicated as treatments that should be further investigated [152]. In a review of 19 randomized controlled studies conducted with adolescents and focusing on suicide attempts or self-harm, it was found that the proportion of adolescents who self-harmed during the follow-up period was lower in intervention groups (28%) compared to the control group (33%). It has been reported to be effective for DBT, CBT, and MBT. However, when the intervention conditions and normal treatment were compared, it was reported that there was no statistically significant difference [153]. In a meta-analysis study conducted by adding nine new studies to the study conducted in 2015, it was found that DBT in adolescents meets the standard to be classified as a “well-established intervention” to reduce SHB, and it was classified as “probably effective” in reducing SHB [154, 155]. In addition, it has been shown that certain elements such as a family-centered approach, the inclusion of skill training, and a longer treatment duration increase the effectiveness of treatment in interventions [155]. In another study evaluating 17 studies, evidence for the effectiveness of DBT was reported, while insufficient evidence for the beneficial effects of CBT, MBT, adaptation development approaches, family interventions, or remote contact interventions was reported [156]. In a meta-analysis study in which 25 randomized controlled studies were included, it was reported that DBT had moderate effects on SHB and showed clinically significant differences. In the study, it was found that other types of therapeutic interventions did not show improvement compared to active control interventions [22]. In a recent review in which 112 randomized controlled studies conducted with child adolescents were reviewed, it was reported that the effects of all intervention methods for SHB were not significant [157]. In the study, it was stated that despite increasing research in recent years, intervention methods do not provide effective improvement [157]. In another recent study in which 26 articles and 23 short intervention methods for short interventions (total duration not exceeding 240 minutes) were examined, only six intervention methods were reported as positively effective, and only one of them was described as “probably effective” [158]. As a result, despite more than 50 years of research on prevention and treatment, it seems that current intervention methods are not very effective [158].

8.2 Pharmacological treatment

There is currently no evidence-based pharmacological treatment method for SHB [157]. In the guidelines, it is reported that studies conducted in adolescents related to SHB are incomplete and a specific treatment agent cannot be recommended with the available data [143, 159]. It is also stated that treatment with pharmacological agents is generally less common compared to psychosocial interventions due to concerns about the risk of increasing the severity of SHB [156, 159]. It is mentioned that in the pharmacological treatment of SHB, the treatment of psychiatric disorders observed in SHB is at the forefront [143, 150, 159]. For example, it has been reported that although the first preferred treatment option in depressed adolescents is the pharmacological agent SSRIs, they have little effect on SHB, but they do not increase SHB rates [159]. However, a 2018 report published by the FDA claimed that there is a potential increase in suicidal thoughts and behavior in adolescents due to antidepressant treatment interventions (as discussed in a US Food and Drug Administration-FDA- warning in 2004). In studies related to antipsychotics, it has been reported that their effects on SHB in child adolescents are insufficient and there are not enough studies [160]. A review of 251 studies evaluating the effectiveness of psychotropic drugs for SHB reported that there was an 8% decrease in the rate of SHB and a 0.2% decrease in symptom severity, as well as antipsychotics, citalopram, and ketamine had a larger-than-average effect size [161]. In addition, all age groups were included in the study, and it was determined that children and adolescents had a lower treatment effect size compared to adults [161]. It is stated that in SHB, pharmacological sedation can be used when acute psychopharmacological intervention is needed, especially in cases of severe internal tension (with an urge to self-injure) [143]. However, some points should also be emphasized. Higher rates of SHB have been reported in people taking benzodiazepines in the TORDIA study [162]. In a different study, it was reported that there was a lack of efficacy in the treatment of SHB with benzodiazepines [163]. In the guidelines for the treatment of SHB in children and adolescents, it has been reported that the use of benzodiazepines should be limited to clearly defined cases, inpatients can be evaluated due to the ease of follow-up, and the risk-benefit ratio should be evaluated individually. In addition, it has been stated that if they are tolerated, conventional antipsychotics with lower potency can be administered [143]. Moreover, some agents also take place in the search for new treatments. One of them, N-acetylcysteine (NAC), is a dietary supplement that is being studied as a potential treatment for various psychiatric disorders, largely due to its ability to cross the blood/brain barrier and increase levels of glutathione, the main antioxidant in the brain. In a study conducted with adolescents, it was reported that the frequency of SHB decreased after 8 weeks of NAC treatment (n = 35) [164]. In the study, it was reported that there was no relationship between the decrease in the frequency of SHB and the decrease in the depression scale, and based on this, it was stated that the role of NAC in reducing SHB and reducing depression may be independent of each other [164]. However, interpretation of the results of the study is limited due to the absence of a placebo control group and the open-label nature of the study. As a result, the pharmacological agent to be selected for the treatment of SHB is based on personal variables, potential interactions with other drugs, and environmental characteristics [143].

9. Preventing self-harming behavior

Given the early age of onset of SHB, it is stated that prevention efforts should be made during early adolescence, especially during elementary and secondary school years, and considering the number of hours students spend in school, school environments are ideal environments for implementing prevention programs. Regarding prevention, the guidelines state that the effectiveness of prevention programs cannot be interpreted due to the lack of available studies [143]. There are various primary and secondary prevention programs focusing on mental health in general (e.g., Happyles and DBT in schools) and studies focusing on suicide prevention in schools (e.g., the Saving and Empowering Young Lives in Europe (SEYLE) [165]), but the effectiveness of these studies in terms of SHB is unclear [166]. Although there has been an increase in studies on SHB in recent years, it is emphasized that there is a lack of studies that are accessible to more people in particular. In a school-based prevention program (The Signs of Self-Injury (SOSI)) conducted by Muehlenkamp et al., it was aimed to increase knowledge about SHB, improve help-seeking attitudes and behaviors, and reduce SHB through psychoeducation for both students and school staff [167]. In this study, where a total of 274 adolescents were evaluated, and pre and post were compared, it was shown that the prevention program increased knowledge among students, improved their attitudes and intentions to seek help, and did not cause an iatrogenic effect (i.e., an increase in SHB thinking and behavior), but the rate of seeking help did not change [167]. Recently, a two-stage study was carried out in a school-based prevention program conducted with 651 school students [166]. This prevention program (Happyles), which focuses on improving general mental well-being and social ties, consisted of a combination of the SHB psychoeducation module (HappylesPLUS) in the second stage [166]. In the results of the study, it was reported that there was no iatrogenic effect, there was a decrease in SHB rates in the future, and emotional awareness increased, but there was no change in seeking help for mental illness [166]. A program consisting of modules on adolescent transformation, body image self-esteem, and emotion regulation with a psychoanalytic approach was implemented in a school-based peer education program for adolescents (NSSI-PEP) conducted during the COVID period [168]. In the results of the study, significant changes in emotion regulation abilities, self-esteem, and body perception were reported [168]. Also, the protocol of the first randomized controlled study (DUDE – Du und deine Emotionen/You and your emotions), which develops and evaluates a universal prevention program with follow-up measurements to prevent NSSI, has been published in the literature. According to this protocol, it is planned to work with 3200 young people in the study, including treatment and active control group, based on a skill-based approach, and it is planned to implement the “Stress-free through the school day” intervention program developed on the basis of DBT and CBT [169].

10. Conclusion

SHB is an important mental health problem that is common during adolescence all over the world. Epidemiological studies have reported that this disorder may begin in childhood, and it has also been shown that it is not limited to adolescence due to its negative consequences, such as other long-term mental disorders and suicide. SHB can emerge alone, as well as it can also occur in the course of many mental disorders. In the DSM-5, it was classified as a disorder for which more research was needed. However, there are still discussions in the literature about its denomination and its place in the diagnostic classification. This situation causes difficulties in the diagnosis and differential diagnosis of SHB. In studies on risk factors, it has been associated with bullying, media influence, family-related factors, and adverse life events in childhood. Although there have been studies related to the HPA axis and the endogenous opioid system in its neurobiology, the clear etiology has not been clarified. SHB is important in terms of its diagnosis, treatment, detection of its risk factors, and prevention, both because of its repetitive nature, its association with other mental disorders, and because it is an important predictor for suicidal behavior. Despite the increasing studies on its treatment in recent years, a clear treatment guide has not been created. Although efficacy has been shown in its treatment, especially with DBT, MBT, and CBT-based treatments, it is reported that more studies are needed for verification. In addition, for the pharmacological treatment of SHB, there is not enough evidence yet.