Non-Suicidal Self-Injury: Prevalence, Risk and Protective Factors

A substantial minority of young people engages in serious self-harm. This article explores the prevalence, risk and protective factors, types, and warning signs of NSSI.

Related articles: Non-Suicidal Self-Injury: Context, Forms and Functions, Working with Shame: Interventions for Deep Emotional Healing.

Introduction

In the first article of this series, we detailed the forms that non-suicidal self-injury, or NSSI, commonly takes and utilised the Four Function Model to explain what functions it serves for those who engage in it. Today we look at its prevalence, the risk and protective factors, the variations, and what the warning signs are that it may be occurring.

Prevalence

While by definition those engaging  in NSSI do not intend to die, NSSI (specifically) and self-harm (as the broader category) do elevate the risk for suicide, so we need to know: just how common is the practice of deliberately harming oneself? We examine here prevalence statistics in both Australia and the United States.

For clarity, “self-harm” below refers to deliberately inflicting injury or poisoning on oneself, regardless of suicidal intent. We talk about the practice of self-injury in the broader context in this article because hospital or emergency department (ED) records do not always reflect intention, so it is not always known whether the seriously bleeding (or otherwise self-harmed) person intended to die when they hurt themselves. We work with two sources of data; health-system statistics typically track hospital or ED encounters for this behaviour, while population surveys capture self-reported behaviour across the community.

Australia

The Australian Bureau of Statistics’ most recent National Study of Mental Health and Wellbeing (reference period 2020–2022; released 5 October 2023) reports that 8.7% of Australians aged 16–85 years have self-harmed at least once in their lifetime, and 1.7% did so in the previous 12 months—equating to about 1.7 million people (lifetime prevalence) and approximately 342,000 in the past year (ABS, 2020-2022).

Health-service data provide a complementary, more acute lens. National monitoring by the Australian Institute of Health and Welfare (AIHW) shows about 24,800 hospitalisations for intentional self-harm in 2022–23, with a national rate around 95 per 100,000 population (noting substantial variation by state/territory; for example, the Northern Territory’s rate was roughly double the national figure). Rates are highest among adolescents and young adults, particularly females. These figures reflect treated episodes rather than community prevalence, but they indicate the scale of clinically significant harm presenting to hospitals (AIHW, 2023-2024).

United States

The most recent national indicator for nonfatal self-harm in the U.S. is tracked in Healthy People 2030 objective IVP-19, which compiles CDC (Centers for Disease Control and Prevention) surveillance data. In 2022, the U.S. emergency department (ED) visit rate for nonfatal intentional self-harm was 163.5 per 100,000 (age ≥10 years), up from a 2017 baseline of 151.3. This national rate underscores a persistent burden on EDs and contextualises recent concern about youth mental health (Healthy People 2030, 2025).

Trend analyses from CDC’s National Syndromic Surveillance Program add nuance: ED visits for suicide-related behaviours among adolescents (a closely related indicator) displayed pronounced seasonal peaks during school terms from 2018–2023, with particularly elevated patterns among females in several recent years. While these reports focus on suicide-related behaviours rather than all self-harm, they align with broader signals of rising or persistently high acute presentations (Radhakrishnan et al, 2023).

For context on scale, CDC burden-of-injury work estimated nearly 500,000 nonfatal self-harm ED visits in 2019, highlighting the large absolute numbers associated with these rates (the most recent nationally compiled count). Although that count predates the 2022 rate above, it remains a useful order-of-magnitude indicator (Geller et al, 2022).

Interpreting and comparing the figures

Cross-national comparisons should be made cautiously. Australia’s community prevalence (ABS) describes how many people report any self-harm over a time window, whereas both countries’ service-based rates (AIHW hospitalisations; U.S. ED visits) capture only events severe enough to present to hospital/ED and are influenced by healthcare access, coding, and care-seeking behaviour. Nevertheless, the latest data point to three consistent patterns:

1. Self-harm is common at the population level in Australia, with roughly 1 in 12 adults reporting lifetime self-harm and about 1 in 60 reporting past-year self-harm (ABS, 2020-2022).
2. Acute, treated self-harm remains a substantial health-system burden in both countries, with Australia recording about 24,800 hospitalisations in 2022–23 and the United States showing a national ED rate of 163.5 per 100,000 in 2022 (AIHW, 2023-2024; Healthy People 2030, 2025).
3. Adolescents and young adults—especially females—bear disproportionate risk for hospital/ED-treated self-harm or suicide-related presentations, a pattern repeatedly observed in the latest monitoring reports (AIHW, 2023-2024; Radhakrishnan et al, 2023).

Key risk and protective factors

Self-harm is multi-determinant, with converging individual, interpersonal, contextual, and even neurobiological drivers. Here we outline the risk and protective factors that either exacerbate the behaviour or help reduce it.

Key risk factors

Robust syntheses identify these factors as potentially escalating NSSI:

• Psychiatric comorbidity and affective dysregulation. Depression, anxiety, and other mood disorders are consistently associated with self-harm; emotion dysregulation is a cross-cutting, empirically supported risk factor in longitudinal and meta-analytic work (Wolff et al, 2019).
• Prior self-harm and suicidality. Past self-harm strongly predicts recurrence and elevates risk for future suicide attempts; NSSI and suicide attempts co-occur more than expected by chance (Fox et al, 2015).
• Trauma, adversity, and family factors. Childhood maltreatment, adverse family-life events, and parent–child relational trauma are linked to increased risk. Bullying victimisation and peer conflict also contribute (Martin et al 2016).
• Demographic and developmental factors. Adolescence is the peak risk period in both Australia and the United States; females account for most non-fatal self-harm presentations, though sex differences vary by measure and setting (AIHW, 2023-2024).
• Minority stress and social determinants. Experiences of discrimination, socioeconomic stressors, remoteness/limited service access, and community-level disadvantage are associated with higher prevalence—patterns documented in Australia’s Youth Self-Harm Atlas and observed in U.S. surveillance for suicide-related outcomes (Radhakrishnan et al, 2023; Geller et al, 2022; AIHW, 2023-2024; AIHW, n.d.).

Key protective factors and service patterns

Across settings and occurring – as do risk factors – across categories of aetiological factors, connectedness (to family, school, and community); access to timely, culturally safe care; and skills for emotion regulation are associated with lower risk, and are emphasised in both Australian and U.S. public-health guidance (Verlenden et al, 2024; AIHW, 2023-2024). In Australia, AIHW’s monitoring shows that intentional self-harm hospitalisation rates are highest in youth, with recent declines among women overall; state/territory rates vary and are often above national averages in Queensland, South Australia, and the Northern Territory (AIHW, 2023-2024). In the U.S., CDC documents the substantial ED burden of self-harm among adolescents, reinforcing the need for upstream prevention and post-discharge follow-up (Gaylor et al, 2021).

It’s also important to know the types of self-harming behaviours and what the warning signs are.

Varieties of self-harming behaviours

Among those individuals who deliberately inflict injury upon their own bodies, we can distinguish between several primary varieties of self-harm, each characterised by a different pattern, degree of severity, and underlying function.

Major self-mutilation

• Definition. Major self-mutilation refers to rare but extreme forms of self-inflicted injury, such as eye enucleation (i.e., the complete removal of the eyeball), castration, or limb amputation. These behaviours are most commonly associated with acute psychotic states, severe substance intoxication, or extreme religious delusions.
• Clinical features. Episodes tend to occur suddenly, often in individuals with untreated psychotic disorders such as schizophrenia. Unlike most NSSI, major self-mutilation is not repetitive and is usually a one-time catastrophic event.
• Implications. It represents a psychiatric emergency requiring immediate medical stabilisation and intensive psychiatric intervention (Favazza, 1998; Large et al., 2009).

Stereotypic self-mutilation

• Definition. Stereotypic self-mutilation involves repetitive, rhythmic, and fixed patterns of injury, such as head banging, self-biting, or repetitive hitting of the body.
  Clinical features. These behaviours typically appear in individuals with developmental disabilities, autism spectrum disorder, or intellectual disability. They may occur many times per day, often outside conscious control, and are sometimes linked to sensory dysregulation or self-stimulation.
  Implications. Treatment often involves behavioural interventions (e.g., applied behaviour analysis), environmental modifications, and, in severe cases, pharmacological support (Symons et al., 2004).

Superficial/moderate NSSI

• Definition. This is the most common and widely studied category, often what clinicians mean by “NSSI” and certainly the type of self-harm on which we have focused in this series of articles. It involves behaviours such as cutting, burning, scratching, hitting, or interfering with wound healing.
• Clinical features. Episodes are usually repetitive and deliberate, often serving intrapersonal functions (e.g., emotion regulation, relief from tension, escape from dissociation) or interpersonal functions (e.g., signalling distress). It typically emerges in adolescence and may persist into adulthood.
• Implications. While injuries are medically less severe than in major mutilation, this category is strongly linked to psychiatric comorbidity and elevated risk for later suicide attempts (Klonsky, 2007; Nock, 2009).

Culturally sanctioned self-injury (contextual note)

Some behaviours, such as ritual scarification or piercings, may resemble self-injury but are culturally normative and not considered psychopathological. Clinicians must distinguish between pathological self-harm and culturally sanctioned practices (Favazza, 1998).

Understanding the varieties of self-harm provides clinicians and educators with a clear framework for differentiating between major, stereotypic, superficial/moderate, and culturally sanctioned behaviors. However, classification alone is not sufficient. In practice, NSSI often remains hidden, and recognition depends on identifying subtle physical, behavioural, and emotional indicators.

Next we get even more granular, highlighting the warning signs that suggest NSSI may be occurring and linking them to the clinical implications. Taken together, these sections move us from a conceptual understanding of self-harm to practical detection strategies, equipping you to respond with greater accuracy, sensitivity, and timeliness.

Warning signs of NSSI

Because NSSI is often concealed due to shame or fear of stigma, early detection depends on awareness of behavioural, physical, and psychological warning signs. Note here that not all the indicators are within the purview of the clinician to observe. With regard to some of the indicators below, especially if you are working with adolescents, there may be no way to observe the warning sign in session. When self-harm is suspected, others living with the client (e.g., parents and siblings) may be able to contribute to the overall clinical picture.

Physical indicators

• Unexplained wounds: Repeated cuts, burns, scratches, or bruises without sufficient explanation.
• Use of concealing clothing: Long sleeves or pants in warm weather, wristbands, or heavy makeup to cover injuries.
• Frequent injuries in patterns: Injuries clustered in particular body regions (e.g., arms, thighs).

(Klonsky & Muehlenkamp, 2007; Whitlock et al., 2006).

Behavioural indicators

• Possession of tools: Razors, lighters, sharp objects, or other implements without clear non-harmful use.
• Avoidance of activities: Withdrawal from sports, swimming, or medical visits to prevent others from seeing injuries.
• Isolation and secrecy: Spending extended time alone in bathrooms or bedrooms; reluctance to discuss activities.
• Online activity: Engagement with internet forums or social media that depict or encourage NSSI.

(Whitlock et al., 2006; Lewis & Seko, 2016).

Emotional and psychological indicators

• Rapid mood shifts: Sudden relief or calmness after periods of high distress, which may follow an episode of NSSI.
• Self-critical or hopeless talk: Statements reflecting worthlessness, self-hatred, or inability to cope.
• Comorbid symptoms: Presence of depression, anxiety, trauma symptoms, or borderline personality traits, all of which increase risk.

(Nock, 2010; Bentley et al., 2015).

Clinical implications

With many health concerns, early, comprehensive effort to assess for the suspected condition is paramount to reduce risk of escalation or worsening. This is also true for issues of self-harm, with the further caveat that you will be more likely to ascertain that self-harm is occurring if you can create a stigma-reducing environment, validating the client. Hence, these are the implications of spotting warning signs of NSSI:

1. Early identification. Awareness of warning signs is critical for educators, parents, and clinicians, as individuals often conceal NSSI. Routine, sensitive inquiry in high-risk populations (adolescents, those with depression or trauma histories) improves detection.
2. Comprehensive assessment. Distinguishing between major, stereotypic, and superficial/moderate forms of self-harm allows for appropriate risk stratification. Major mutilation requires urgent psychiatric and surgical intervention, whereas stereotypic self-harm benefits from behavioural and environmental management.
3. Risk of escalation. Even when initially superficial, NSSI is one of the strongest predictors of future suicide attempts. Clinicians must assess not only the injuries but also their frequency, functions, and associated psychopathology.
4. Stigma reduction. Because many who self-injure feel ashamed, clinicians should adopt a validating, nonjudgmental stance to foster disclosure and engagement in care (Ribeiro et al., 2016). Further reading: Working with Shame: Interventions for Deep Emotional Healing.

ConclusionThe most current official data indicate that self-harm affects a substantial minority of young people each year and continues to drive high volumes of hospital or ED presentations in both Australia and the United States. As therapists, we need to familiarise ourselves with the key risk and protective factors, along with the various varieties of self-harm. We need to know what the various warning signs of NSSI are on physical, behavioural, and psychological levels. By attending to these signals, along with youth-focused surveillance, we can recognise the ongoing need for prevention, early identification, and timely care.

Key takeaways

• A meaningful minority of people – especially youth – in both Australia and the United States engage NSSI.
• Psychiatric co-morbidity, affective dysregulation, prior self-harm and suicidality, trauma and adversity, and social/demographic factors all constitute risk factors for NSSI, while connectedness, access to timely, culturally safe care, and skills for emotion regulation are protective factors.
• Self-harm can be major self-mutilation or stereotypic self-mutilation, but most NSSI is categorised as “superficial/moderate”, though still important to detect early as it increases risk for suicide.
• Warning signs that NSSI is occurring can range from physical (e.g., unexplained wounds) through behavioural (e.g., avoidance of activities) to emotional/psychological (e.g., mood shifts and co-morbid symptoms).
• The clinical implications include that early identification, stigma reduction, and comprehensive assessment are important to reduce risk of escalation.

Questions therapists often ask

Q: How should I frame prevalence data when discussing NSSI with clients or parents?

A: Keep it grounded and non-alarmist. The article makes it clear that NSSI is relatively common, especially in adolescence, with notable peaks around mid–high school years. Presenting it as a recognised phenomenon—not a rarity or a sign of pathology in itself—helps reduce shame and opens the door to honest discussion. Emphasise that prevalence differs by age, gender, and context, and that many young people engage in NSSI as a maladaptive coping strategy rather than a wish to die.

Q: The risk factors list is long. Clinically, where do I start when assessing a young person?

A: Prioritise proximal factors that increase immediate vulnerability: emotional dysregulation, high reactivity to stress, and current interpersonal strain. The article highlights these as common drivers. Once safety is established, broaden the lens to distal contributors—trauma history, identity distress, marginalisation, perfectionism, or neurodevelopmental conditions. Think of it as widening concentric circles rather than tackling everything at once.

Q: How can I distinguish between “risk factors” and what’s actually maintaining the client’s NSSI?

A: The article makes the point that risk factors explain susceptibility, but maintaining factors often live in the here-and-now: short-term relief from distress, avoidance of overwhelming emotions, or functional reinforcement from peers or online communities. In session, track what the behaviour does for the client rather than what caused it historically. That functional focus is usually the most clinically actionable.

Q: Protective factors sound nice in theory, but which ones genuinely shift the clinical trajectory?

A: The most potent ones highlighted in the article are emotional competence, supportive relationships, problem-solving skills, and a sense of belonging. These aren’t abstract concepts—each can be strengthened through therapy. Even improving just one protective factor (for example, helping a client build one reliable peer connection) can meaningfully reduce NSSI frequency.

Q: When a client has several risk factors but also strong protective factors, how should I weigh the overall picture?

A: Think of it as a dynamic balance rather than a scorecard. The article underscores that protective factors don’t eliminate risk, but they buffer it. If a teen has trauma history and emotional volatility but also secure parental attachment and good help-seeking behaviours, you can expect volatility but also resilience. It helps orient treatment: shore up what’s already working, then strategically target the high-impact risks that are tipping them into self-injury.

References

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• Australian Institute of Health and Welfare (AIHW). (2023-2024). Intentional self-harm hospitalisations by states and territories. AIHW. Retrieved on 26 August 2025 from: https://www.aihw.gov.au/suicide-self-harm-monitoring/service-use/hospitalisations/hospitalisations-by-states-and-territories
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