Many different factors may increase a person's risk of self-injury. People who have self-injured in the past have a greater likelihood of repeating the pattern. Females who self-injure outnumber males. Teenagers and young adults make up the majority of self-injurers. Usually first occurring at puberty, self-injury may continue for up to 10 years or longer if left untreated.

A history of physical or sexual abuse may increase a person’s risk of self-injury. Nearly 50 percent of self-injurers were physically or sexually abused as children, according to the National Mental Health Association (NMHA).

Self-injury may be associated with many different mental disorders, including:

• Mood disorders. Disorders that affect a person’s mood and impair functioning, such as major depression and bipolar disorder.
  

  

• Personality disorders. Conditions involving chronic patterns of behavior that can worsen stress and interpersonal difficulties. An example is borderline personality disorder (BPD), which involves significant personal instability and impulsive behavior. Self-mutilating behavior (e.g., cutting) can be a symptom of BPD and is among the diagnostic criteria for BPD identified by the American Psychiatric Association (APA).
  
  
• Anxiety disorders. Disorders associated with debilitating levels of worry and fear, such as post-traumatic stress disorder (PTSD).
  
  
• Eating disorders. Disorders characterized by altered eating habits (e.g., eating too little or binging-and-purging) due to obsessive and distorted thoughts regarding body image. This behavior may lead to feelings of shame and physical harm to the body. Examples include anorexia nervosa and bulimia nervosa.
  
  
• Substance abuse. The chronic use of alcohol or drugs that alter mood or behavior, causing significant disruption in a person’s life.
  

  

Almost all self-injurers have difficulty talking about their feelings. Ninety percent report being discouraged from expressing emotions (especially anger and sadness) by caregivers, according to the NMHA. An inability to cry, scream or yell may lead to self-injury as a way to express emotional pain.