Sometimes people with bipolar disorder, depression, and other mood disorders have episodes when they feel extremely sad, hopeless, anxious, or confused. When these emotions get too intense, the person may harm themselves with acts of self-injury.

Self-injury (also referred to as cutting, self-mutilation, or self-harm) is a desperate attempt to cope with overpowering negative emotions, such as extreme anger, frustration, and anxiety.  It is usually repetitive, and not a one-time act (such as a suicide attempt might be).

One form of self-injury is cutting of the skin with a razor, knife, or other sharp object.  Other forms of self-injury may include burning, scratching, biting, hitting/bruising, banging their head, or picking at their skin. Sometimes they may even pull out their hair.

Self-injury can be an impulsive behavior, or it may be a regular (ritualistic) behavior.  Either way, it is a way to get immediate release for built-up anxiety or stress, to regulate intense emotions, as a coping technique, or as a distraction technique.

No matter how self-injury is done or the motivations behind it, however, it is an unhealthy and dangerous act and can leave deep scars, both emotionally and physically.

Self-injury is an unhealthy way to deal with negative feelings, and is an indication that the person definitely needs help.

People who self-injure are also prone to abuse alcohol and drugs.  One way of thinking is that they do this to "self-medicate" their bipolar symptoms – but like drugs and alcohol, self-injury only provides a "quick fix."

Suicide is a major risk for people with bipolar disorder. Between 25% and 50% of those with bipolar disorder attempt suicide, and 15% die by suicide.

 However, people who engage in self-injury to try to cope with negative feelings are not necessarily suicidal.

Even though self-injury and suicide are different, self-injury still should not be brushed aside as a small problem. The very nature of self-injury is physical damage to the person's body, which is a cause for concern.

If your loved one has been exhibiting signs of self-injury, it is crucial that they get help.  This behavior will not go away by itself.

With proper treatment, they can learn to keep their moods in check, and can avoid overwhelming feelings of sadness, helplessness, hopelessness, anxiety, stress, and other negative feelings, that may lead to destructive behaviors like self-injury.

Sometimes a change in medication and/or dosage is all that may be needed to regulate your loved one's moods and prevent their self-injury.

http://www.webmd.com/bipolar-disorder/guide/bipolar-disorder-self-injury?page=2