Self-mutilation, more commonly called non-suicidal self-injury (NSSI), is the deliberate, self-inflicted destruction of body tissue without the intent to die. It includes behaviors like cutting, burning, hitting, and severe scratching. Roughly 17.7% of adolescents and 5.5% of adults have engaged in it at some point, making it far more common than most people realize.
The term “self-mutilation” has largely fallen out of clinical use because it carries heavy stigma and doesn’t accurately capture why people engage in the behavior. The current clinical term, non-suicidal self-injury, emphasizes a critical distinction: this behavior is not a suicide attempt, even though it involves physical harm. Understanding that distinction is essential to understanding the behavior itself.
What It Looks Like
Self-injury takes several forms, and most people who engage in it use more than one method. Cutting or carving the skin is the most common, reported by roughly 1 in 5 people in clinical samples. Burning with cigarettes, lighters, or matches is the next most frequent, followed by blunt-force methods like hitting oneself, banging one’s head, or punching walls. Less severe forms include severe scratching, biting, inserting objects under the skin, and deliberately preventing wounds from healing.
The injuries typically follow patterns, often concentrated on the arms, thighs, or stomach, areas that are easy to reach and easy to hide. Some people injure in the same spot repeatedly. Others spread injuries across different areas of the body.
Why People Do It
The most important thing to understand about self-injury is its function. It is overwhelmingly used as a way to manage emotions that feel unbearable. In research asking people directly why they hurt themselves, 85% rated “to release emotional pressure that builds up inside of me” as their primary reason. Other top reasons included “to control how I am feeling” and “to get rid of intolerable emotions.”
Self-punishment is the second most common motivation. About 69% of people who self-injure endorse reasons like “to express anger at myself,” but most rate this as a secondary reason rather than the main driver. Less common motivations include wanting to feel something when emotionally numb (reported as primary by 18%), seeking an adrenaline rush (21%), communicating distress to others (5%), and avoiding suicidal urges (5%).
What ties most of these functions together is that self-injury works, at least temporarily. The relief it provides is real, which is part of what makes it so difficult to stop.
What Happens in the Body
The temporary relief from self-injury has a biological basis. When the body experiences pain, it releases its own natural painkillers, chemicals in the same family as morphine. These substances don’t just dull physical pain; they also suppress emotional distress and activate reward pathways in the brain.
Research has found that people who self-injure have significantly lower baseline levels of these natural painkillers compared to people who don’t. This means they may be walking around with less of the body’s built-in emotional buffering system, which could help explain both why emotional distress feels so overwhelming and why physical pain provides such noticeable relief. People who self-injure also show higher pain tolerance than average, which may reflect changes in how their pain system operates over time.
The stress response system also appears to function differently in people who self-injure. The body’s natural painkillers are deeply intertwined with the hormonal stress response, and disruptions in one system can affect the other. This creates a biological loop: emotional distress triggers the urge, physical pain provides chemical relief, and over time the behavior can take on a compulsive quality.
Who Is Most Affected
Self-injury most commonly begins between ages 12 and 14, with 13 being the single most reported age of onset. This timing aligns with a period of intense emotional, social, and neurological development during early adolescence.
Female adolescents are affected at higher rates than males: about 21.4% compared to 13.7%. Prevalence drops with age, falling to around 13% in young adults and 5.5% in the general adult population. Questioning one’s personal or sexual identity and social isolation are both recognized risk factors.
Self-injury rarely occurs in isolation from other mental health challenges. Depression is the most common co-occurring condition. In one large study of adolescents with depression, 76% also engaged in self-injury. Going the other direction, over 81% of adolescents who self-injured also met criteria for depression. Anxiety disorders, eating disorders, post-traumatic stress, substance use disorders, and borderline personality disorder all co-occur at elevated rates as well.
How It Differs From a Suicide Attempt
Self-injury and suicide attempts are related but distinct behaviors. The core difference is intent: self-injury is done to cope with life, not to end it. People who self-injure are typically trying to feel better, feel something, or release pressure. People who attempt suicide are trying to escape life entirely.
The patterns of behavior also look different. Self-injury tends to be frequent and repetitive. In one study, nearly half of participants had cut themselves within the past month, and about a quarter had done so in the past week. Suicide attempts, by contrast, are less frequent events, with about 46% of people with a history of attempts having made one in the past year.
That said, the relationship between the two is not simple. A history of self-injury is one of the strongest predictors of a future suicide attempt. Researchers believe this is partly because repeated self-injury may reduce the fear and pain associated with harming one’s body, which can lower the threshold for more lethal behavior over time. The two behaviors exist on a spectrum rather than in completely separate categories, and distinguishing between them in any individual case can be genuinely difficult, even for clinicians.
Signs That Someone May Be Self-Injuring
Self-injury is typically a private behavior, and people often go to significant lengths to conceal it. Physical signs include unexplained cuts, scratches, bruises, bite marks, or burns, often in patterns. Scars that appear in clusters or lines on the arms, legs, or torso are common. Wearing long sleeves or pants in warm weather to cover these marks is a frequent behavioral indicator.
Other signs are less obvious: keeping sharp objects or lighters without a clear reason, frequent claims of accidental injury, rapid and intense mood swings, social withdrawal, and expressions of hopelessness or worthlessness. None of these signs alone confirms self-injury, but a pattern of several together warrants concern.
How Self-Injury Is Treated
The most effective treatment for self-injury is dialectical behavior therapy (DBT), a structured form of therapy originally developed for people with intense, difficult-to-manage emotions. DBT teaches four core skill sets: how to tolerate distress without acting on it, how to regulate emotions more effectively, how to stay present and grounded, and how to navigate relationships. The goal is to replace self-injury with skills that serve the same emotional function without causing harm.
In a clinical trial of highly suicidal, self-harming adolescents, 54% of those receiving DBT had stopped self-harming by the end of treatment, compared to 37% receiving standard care. These improvements continued to hold through a one-year follow-up. DBT is not a quick fix, but it is the treatment with the strongest evidence behind it.
Other therapeutic approaches, including cognitive behavioral therapy and emotion-focused treatments, also show benefits. Because self-injury so often occurs alongside depression, anxiety, or trauma, effective treatment usually addresses the underlying conditions as well as the self-injury itself. Recovery is common, but it often involves setbacks, and the process works best when the person has consistent support and a therapist trained in working with self-harm.