Self-injury or self-harm is deliberate injury inflicted by a person upon their own body without suicidal intent. These acts may be aimed at relieving otherwise unbearable emotions, sensations of unreality and numbness. The illness is listed in the Diagnostic and Statistical Manual of Mental Disorders(DSM-IV-TR) as a symptom of borderline personality disorder and depressive disorders. It is sometimes associated with mental illness, a history of trauma and abuse including emotional abuse, sexual abuse, eating disorders, or mental traits such as low self-esteem or perfectionism, but a statistical analysis is difficult, as many self-injurers conceal their injuries. Self harmers are often mistaken as suicidal, but in the majority of cases this is inaccurate.

A common belief regarding self-injury is that it is an attention-seeking behaviour; however, in most cases, this is inaccurate. Many self-injurers are very self-conscious of their wounds and scars and feel guilty about their behaviour leading them to go to great lengths to conceal their behaviour from others.

Self-injury in such individuals is not associated with suicidal or para-suicidal behaviour. The person who self-injures is not usually seeking to end his or her own life; it has been suggested instead that he or she is using self-injury as a coping mechanism to relieve emotional pain or discomfort.

---- Wikipedia (http://en.wikipedia.org/wiki/Self-injury)

What is self-harming?

Self-harming is when people cause themselves physical pain that alters their mood state (how they feel inside). Some people harm themselves because they feel disconnected and isolated from everybody, and hurting themselves is the only way they feel real or connected.

Self-harming behaviours can include:

cutting their skin with knives or any sharp object
burning their skin
hitting their body with an object or fists (like punching the wall)
deliberately falling when doing something like extreme sports
picking at their skin
swallowing pills or sharp objects
pulling at their hair (hair pulling can also be a habit).

Why do people start harming themselves?

Self-harming can be a way that people deal with feelings of:

helplessness, despair and low self-esteem
anger, loneliness, shame and guilt
not having control over their life
being 'out of it' – so the only way to feel 'real' is to cause physical pain to themselves.

Some self-harm is related to severe emotional pain. When people have experienced abuse or violence, it often re-appears as emotional pain in later life. Some people have said that:

When they hurt themselves physically, it helps take away the emotional pain.
Self-harm makes internal pain visible on the surface. It is showing that there is a problem that needs to be addressed.
Self-harm is a way that people punish themselves for something.

People who harm themselves...

may have difficulty expressing their feelings verbally
may dislike themselves and their bodies
may do it because of difficulties with relationships
may do it because of mental health issues such as depression, anxiety or stress.

---- http://www.cyh.com/HealthTopics/HealthTopicDetails.aspx?p=243&np=293&id=2464