This article presents current evidence describing the epidemiology, course, functions, and psychiatric co-morbidities of non-suicidal self-injury (NSSI) in adolescents. Rates of NSSI in adolescents have risen recently; studies suggest this rise can be partially attributed to subclinical and experimental forms of NSSI. In light of this trend, assessment of adolescent NSSI behaviors by nurse practitioners is an important step in providing mental health services to adolescents who need them. In this article, Macdonald’s “Stages of Adolescent Substance Use” is adapted to a model of adolescent self-injury called “Stages of Adolescent NSSI Behavior,” and clinical responses according to each stage are proposed.

Non-suicidal self-injury in adolescents is increasing in incidence in the United States and elsewhere.^1-4 At the same time, the healthcare community’s understanding of the importance of NSSI has changed; the commonality of NSSI precludes viewing this phenomenon as a hallmark of fringe pathology, as it may have been viewed in the past.⁵ In a healthcare system that increasingly requires primary care NPs to evaluate mental health concerns, it is not sufficient to label any and all self-injurious behaviors as “psych issues” and then refer the patient elsewhere. This article provides the current understanding of adolescent self-injury, as well as tools for evaluation and management of NSSI by NPs.

The model proposed by the authors here, “Stages of Adolescent NSSI Behavior,” is based on Macdonald’s “Stages of Use” model, which stratifies adolescent drug and alcohol use into five levels of severity.⁶ First presented in 1984, Macdonald’s stages describe the progression from no use at all, to experimentation, to daily use, and finally to severe substance abuse that precludes one from functioning in any realm of life in a normal or typical way.⁶ By comparing adolescent NSSI to adolescent substance use and suggesting ways to separate experimental and subclinical forms of NSSI from more serious manifestations, the “Stages of Adolescent NSSI Behavior” can help NPs understand that there are varying degrees of NSSI behavior. Careful assessment of behavior allows NPs to reserve emergency mental health services for patients who need these services most, while maintaining the trust of their teenaged patients.

Describing Non-suicidal Self-injury

Non-suicidal self-injury is a set of behaviors ranging from commonplace actions such as nail-biting to the intentional infliction of injuries serious enough to require immediate attention in an emergency department.^3,4,7,8 Favazza⁹ advanced a widely-accepted definition of NSSI as the “deliberate, direct destruction or alteration of body tissue without conscious suicidal intent.” NSSI usually takes the form of cuts, scratches, or burns on the arms, legs, or front of the torso. These injuries may appear as patterns or words, perhaps favoring one body area over others.^3,4,10 Some experts include provoking fights, skin-picking, and wound interference (ie, picking scabs or delaying/denying treatment for wounds) in the list of NSSI behaviors.^3,7,8 Extreme forms of self-injury, such as breaking bones, self-castration, and eye enucleation, exist, but they are not common in adolescence and are often manifestations of psychosis.⁴ Such severe self-injury is beyond the scope of this article; primary care management for a severely self-mutilating patient necessitates involvement of a team of medical and psychiatric practitioners and social workers.

Frequency in Adolescents—The proportion of individuals who have engaged in NSSI at any point in their lives is unclear because older studies tended to include only inpatients at psychiatric facilities.^1,3 Most authors agree that initial acts of NSSI usually occur at age 13 or 14.^3,7,8,10 Adults self-injure as well, but the behavior typically started at some point in childhood or adolescence.^3,7,10 Jacobson and Gould³ estimated that the rate of NSSI behaviors in non-clinical samples of adolescents was 13%-23%. Statistics in more recent studies indicate that the rate of adolescent NSSI is rising in this country. Although this rise could reflect a relaxation of the social taboo preventing disclosure of NSSI, retrospective data and recent cohort comparisons support the notion that the proportion of adolescents reporting at least one act of self-injury in their lifetime has increased.^1-4,11

Data indicate that large numbers of high-functioning adolescents are engaging in NSSI in transient and sometimes subclinical ways.^1-4,8,11-13 Whitlock et al⁸ reported that 17% of 18- to 25-year-old college students responding to an Internet questionnaire disclosed at least one prior act of self-injurious behavior, but fully 25% of those individuals never repeated the behavior. Although the response rate to the questionnaire was not high enough to draw conclusions about NSSI prevalence in community samples, these numbers suggest that many college-aged individuals experiment with the behavior. 

Klonsky and Olino² found that 205 (25%) of 815 college students in an introductory psychology course reported a history of self-injury; among these individuals, four statistically distinct groups were identified using a latent class analysis. NSSI in the first two groups, comprising almost 80% of the original 205 students, was labeled experimental or mild. Statistical commonalities of persons classified with experimental or mild NSSI were fewer symptoms of anxiety/depression and less severe self-injurious behavior (eg, hair-pulling, self-hitting). The remaining students (22%) were categorized in the third and fourth groups because they had more severe manifestations of NSSI: multiple methods of injury; a higher incidence of anxiety, depression, and borderline personality disorder; and more suicide attempts. Although many members of the first two groups reported acts such as cutting, scratching, or burning, they were more likely to have done so once or twice as opposed to more than 10 times.

Motivations and Psychiatric Classifications—For most adolescents who self-injure, the act of harm is a powerful strategy for improving negative internal states and lessening anxious arousal.^5,10,14,15 Aside from affect regulation, the most common functions of self-injury are self-soothing, communicating needs, achieving support, expressing anger against society, regulating relationships, and averting dissociation.^5,15 Of note, suicidal intention is absent from this list across multiple studies.¹⁵ This variety of motivations for self-injury means that the presence of NSSI does not itself imply any specific psychiatric diagnosis.^10,16

Relationship Between NSSI and Suicide—The motivation to harm one’s own bodily tissue is foreign to most healthcare practitioners; therefore, many of them conflate NSSI with suicidal intent, usually to the detriment of the patient–practitioner relationship. A practitioner who treats every episode of NSSI as a suicidal gesture will likely alienate non-suicidal patients by making them feel misunderstood and, ultimately, not heard or believed.¹⁷ Assumption of suicidal intent also ignores the underlying issue and increases the probability of pursuing ineffective treatment.¹⁸

Although distinction from suicide is a defining feature of NSSI, suicidal ideation and suicide attempts can, and often do, coexist with NSSI.^16,19,20 In a recent study of 2875 students from three universities in the northwestern United States, 490 of them reported a history of NSSI; of this group, 40.3% also reported a history of suicide attempts, suicidal gestures, or suicidal thoughts with a plan.²⁰ In fact, shame associated with being unable to modulate a behavior that breaks social taboos can, in some self-injurers, promote feelings of hopelessness and worthlessness that contribute to suicidal ideation.⁵

Most data suggest that adolescents who regularly self-injure are more likely than non-self-injuring peers to be suicidal, have mood disorders such as depression or anxiety, and report feelings of psychological distress.^1,16,20 Therefore, suicidality and the propensity to engage in mild or infrequent NSSI can be understood as separate states, with the presence of self-injury increasing one’s vulnerability to a suicidal state. In fact, many people who self-injure report using NSSI to avert thoughts of suicide and feelings of depression.^5,10,15 Although concurrence of NSSI and suicidal thoughts/gestures may be important, NPs need to distinguish between self-injury that presages suicidal behavior and self-injury that reduces the likelihood of suicidal behavior (albeit not in a constructive manner). Regardless, suspicious physical injuries or patient reports of NSSI are abnormal examination findings. Suicidal intent, as well as abuse, must be included on the differential diagnosis and then ruled out, as appropriate.

Primary Care Practitioners and NSSI: Assessment is Crucial

Portrayal of adolescent NSSI in the primary care community has been influenced by research that addresses the behavior only in clinical or institutionalized populations.^1,3 This image fosters the belief that self-injury is always a sign of profound mental illness and a well-established habit. As a result, recommendations for responding to NSSI have ranged from coordination of a multidisciplinary team of parents, psychiatrists, school personnel, and the adolescent to immediate psychiatric hospitalization and evaluation.^21-24 This approach ascribes the same level of danger, regardless of the severity or intent of the behavior, to all forms of NSSI.

Psychiatric assessment, therapy, psychotropic medications, family involvement, and even hospitalization are all vital interventions for certain adolescents grappling with NSSI. NPs should never hesitate to refer patients to mental health professionals when resources and willingness are not barriers or when the acuity of symptoms necessitates action. However, given the evolution of NSSI into a commonplace coping mechanism, the role of the NP in assessing severity of the problem is crucial to ensuring that resources such as hospitalization and expedited psychiatric referral are available to those who need these services most.

There are compelling reasons why immediate psychiatric intervention may not be appropriate in every identified case of self-injury, the most obvious of which is that such interventions may not be needed. An example is a highly-functioning adolescent who, at the urging of a peer, experiments one time with self-injury. Another reason to delay the decision about psychiatric referral until a thorough assessment is completed is that scholars agree that incorporation of NSSI into core identity (ie, becoming a cutter as opposed to someone who cuts) signals a worse prognosis, and not all adolescents who engage in this behavior self-identify with it.^9,25 To avoid inadvertently reinforcing identification with NSSI in an experimenting patient, NPs should ascertain the extent, frequency, and meanings of the behavior before deciding on the best initial level of intervention.

The threat of suicide is frequently cited as a crisis situation in which confidentiality must be breached. However, studies using measures of suicidal ideation, reasons for living, and depression have demonstrated a clear distinction between non-suicidal self-injurious teens and actively suicidal teens.19,26 By ruling out suicidal intent with careful assessment, NPs can base referrals to mental health specialists on patient readiness and severity of underlying symptoms.

Assessment of NSSI behaviors not only helps match mental health services with teens who need them most, but, given a non-suicidal adolescent with low level NSSI behavior, it allows for a confidential conversation in which patient concerns about parental involvement or mental health services can be discussed and addressed over time. More so with adolescents than anyone else, issues of confidentiality and empowerment can complicate clinical decisions. Laws regarding adolescent consent to mental health care, which differ from state to state,²⁷ recognize that requiring parental involvement is a deterrent to seeking care. For all sensitive health matters, the Society for Adolescent Medicine calls for adolescents to be afforded the greatest possible extent of confidential care.²⁸

Theoretical Framework

When widespread drug/alcohol abuse was identified in adolescents in the late 1970s, many healthcare practitioners did not know what to do or how to intervene on their patients’ behalf.^29,30 Conversations about substance use/abuse were hindered by social taboo and practitioners’ beliefs that the problem had more to do with morals than with health.²⁹ But clinicians did recognize the importance of identifying possible substance abuse problems in adolescents.³¹ To aid in this assessment, Macdonald6 developed a five-stage model of severity for healthcare practitioners to use; Table 1 summarizes this model.

Non-suicidal self-injury and substance abuse share many features. Each phenomenon is a coping mechanism that harms the self, lacks suicidal intent, and serves a variety of social and psychological functions. Most teens are secretive about either behavior and are likely to go to great lengths to hide evidence of the behavior from adults. As described earlier, many adolescents and young adults report experimenting with self-injury, much as young people are known to experiment with drinking or drug use. In addition, many authors have pointed out that self-injury can become addictive.^9,32 Even those authors who dispute the presentation of NSSI as a traditional addiction concede that it is often experienced as an addictive behavior by those who self-injure.³³

NSSI Assessment Using a Substance Abuse Model

When NSSI is identified in an adolescent—by patient disclosure, parent report, or physical evidence—a clinical response is warranted. Given the similarities between NSSI and substance abuse, Macdonald’s Stages of Use model can be adapted and used as a framework to understand NSSI severity in each case. Table 2 lists proposed stages of adolescent NSSI behavior. Although this model has not been tested, it can serve as a tool for separating patients who may need urgent psychiatric consultations from those who are at low risk for serious self-harm. Research into intermittent and subclinical NSSI is still nascent, but using a model with four stages of severity (and one stage with no behavior) is well supported by the aforementioned latent class analysis by Klonsky and Olino.2 This analysis showed that four levels of behavior provided the best statistical fit for their sample of older adolescents and young adults who self-injure.

To assist NPs in using the Stages of Adolescent NSSI Behavior model, the authors present sets of suggested questions in algorithm format (Figure 1). The diagram is not intended to replace clinical judgment. NPs know many different ways to take a complete history from adolescents; not all questions will be relevant for every patient. Likewise, professional judgment remains the most important tool NPs have to create a plan of care for any particular patient.

Stage 0: No Self-injurious Behavior—The lowest level of self-injury is, of course, no present or past self-injury. Adolescents in this stage may represent a broad range of knowledge and attitudes about NSSI. Although some adolescents may be naïve about the presence of NSSI in their peer group, others will have been exposed to self-injury through music, Internet exploration, movies, and/or having friends who engage in the behavior. When NPs ask teens first about NSSI in the wider peer group (Figure 2), they are giving their patients an opportunity to ask questions about the behavior and vent feelings about how adults or peers responded when someone was discovered to be self-injuring. In Stage 0 adolescents, introducing NSSI into the conversation can help NPs assess patients’ awareness of self-injury and knowledge about resources that can be alternatives to all kinds of self-destructive behaviors.

Stage 1: Experimental NSSI—Stage 1 comprises adolescents’ first act(s) of self-injurious behavior; this experience will help determine whether or not they choose to repeat this behavior. Adolescents in Stage 1 are not yet committed to NSSI as a coping behavior, nor have they taken on the identity of a person who self-injures. The decision to continue or escalate is based primarily on how well the behavior satisfies the person’s motivations—usually, regulation of internal states, expressing need or anger, feeling part of a group, or averting dissociation.^5,10,15 

As previously described, experimental and subclinical self-injury appears to be on the rise among adolescents, with a notable proportion of individuals deciding against further practice.^2,8 Keeping this fact in mind, NPs should explore these adolescents’ attitudes toward further injury to identify those who have tried NSSI but who have found it not worth pursuing. With true experimental behavior, breaking confidentiality or intervening against a patient’s wishes is reserved for extreme circumstances (see Figure 2 and Table 3). Compelling factors might include an expressed intention to escalate the behavior or a dangerous complication of self-injury (eg, a secondary wound infection).

Stage 2: Exploration—Adolescents at Stage 2 consider self-injury an important method of dealing with daily stressors and negative internal states. Because the behavior is incorporated into these adolescents’ repertoire, they may hide necessary tools—such as sharp instruments and bandages—to ensure access should the need arise to engage in NSSI. This stage is a period of exploring NSSI, discovering their own physical and psychological responses to the behavior. They may begin to seek out a peer community online or at school where self-injurious behavior is not aberrant; such communities can provide positive support to self-harming teens, but they also strengthen identification with NSSI behavior, potentially making this behavior more difficult to stop.³⁴

Many adolescents who self-injure continue to do so because, at least in the short term, this behavior “works.”¹⁵ Adolescents in Stage 2 may find NSSI to be an effective coping strategy but deny the behavior even in the face of physical evidence such as scars. At this point, few areas in these adolescents’ lives are obviously dysfunctional because of the self-injurious behavior, although dysfunction in home, school, or social life often precedes NSSI.³ Less obvious signs that self-injury may have become a habit include a change in appearance or peer group, refusal to participate in activities that might expose the arms and the legs, and an inability to explain potentially harmful items in their possession.

Decisions about providing care for Stage 2 adolescents, as with Stage 1 adolescents, are informed by the adolescents’ perception of the problem (see Figures 1 and 2 and Table 3). However, the risks associated with NSSI become greater with more repetition,⁴ so NPs can decide to break confidentiality with fewer problems directly in evidence.

Stage 3: Encapsulation—Adolescents in Stage 3 are no longer experimenting with or exploring NSSI. At this point, NSSI is not one of many coping strategies used but, rather, the primary (if not the only) method used to control negative feelings. NSSI happens regularly, and these adolescents may construct elaborate plans regarding how and when self-injury will occur. In this stage, urges strike at inconvenient times and become more difficult to control; the behavior becomes increasingly difficult to hide.

By this stage, adolescents have probably tried many forms of self-injury; the number of methods of injury is associated with behavior severity.3 Because of the habitual nature of NSSI, adolescents will likely have one or two favorite methods, but behaviors can evolve over time. Physical damage inflicted with NSSI at Stage 3 is greater than that at earlier stages because of mounting difficulty and lack of relief with lesser injury. Anxiety, depression, and hopelessness are likely to be prominent in the clinical picture, as are suicidal ideation and past suicide attempts. NPs are unlikely to be the first persons to notice or suggest that problems exist in adolescents at Stage 3, but the NSSI behavior itself may still be hidden.

Among the adolescents who present to NPs with a history of self-injury, only a small proportion will be in Stage 3 or Stage 4. Because Stage 3 self-injury is marked by patient deterioration, appropriate and immediate intervention is critical (see Figure 2 and Table 3). Whitlock and Knox20 found that, among young adults who disclose self-injury, the likelihood of suicidal ideation or intent increases as the frequency and physical harm of self-injury increases. Therefore, NPs should have a high index of suspicion for suicidal thoughts and behaviors in Stage 3 adolescents. At Stage 3, the critical role of the practitioner is to assess teens’ safety in different spheres of life and to help develop a plan to prevent further decline while treatment is initiated. Specialized self-injury treatment centers, if available in the community, are an appropriate referral site for Stage 3 adolescents.

Stage 4: Pervasive Dysfunction—The final stage of NSSI behavior is characterized by constant self-injurious thoughts and actions; teens have few, if any, functional areas in their lives. Whereas Stage 3 self-injury is difficult for adolescents to control, Stage 4 NSSI is barely, if at all, under adolescents’ control. Such extreme behavior is found almost exclusively in clinical populations^3,7 and is not the typical outcome of adolescents who engage in NSSI. Probability of suicidal thoughts and plans is higher in Stage 4 than in Stage 3, so if adolescents appear to be in Stage 4, NPs need not hesitate to implement immediate psychiatric interventions, including hospitalization. Whenever possible, specialized care is sought for adolescents in Stage 4 (see Figure 2), and treatment takes place in an inpatient setting if patients’ safety cannot be ensured at home. When treatment of such adolescents is passed on to mental health experts, NPs can fill the roles of connecting the family to community services and leading multidisciplinary teams of professionals.

Conclusion

Recent literature strongly suggests that self-injurious behaviors in adolescents have increased in recent years. This increase is likely due, in large part, to adolescents who experiment with self-injury—that is, those who have fewer psychiatric symptoms and fare better than do their clinical counterparts with numerous hospitalizations and psychiatric disorders. High rates of self-injury mean that NPs must be prepared to address this problem during routine health care. Adapting Macdonald’s adolescent substance abuse model to the Stages of Adolescent NSSI Behavior model can help NPs understand NSSI behaviors and guide clinical interventions, follow-up, and referrals. 

Nurse practitioners cannot address the growing problem of non-suicidal self-injury by adolescents without continued research into its etiology, course, and treatment. Empirical study of the Stages of Adolescent NSSI Behavior is needed to shed light on how NP assessment of self-injuring teens can  improve outcomes and conserve resources.  Advocacy for increased access to and funding for mental health care for all young people is vital to ensuring that those resources are there for everyone who needs them.

Emily C. Williams is a family nurse practitioner at Ithaca Convenient Care Center in Ithaca, New York. Alison Moriarty Daley is an associate professor at Yale School of Nursing Master’s Program, Pediatric Nurse Practitioner Specialty, and a pediatric nurse practitioner at the Yale-New Haven Hospital Adolescent Clinic and Hill Regional Career High School School-Based Health Center in New Haven, Connecticut. Joanne DeSanto Iennaco is an assistant professor, Yale School of Nursing Master’s Program, Psychiatric and Mental Health Specialty, in New Haven, Connecticut. The authors state that they do not have a financial interest in or other relationship with any commercial product named in this article. 

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