People with body-focused repetitive behavior disorder may feel tense or anxious just before they engage in nail biting or lip biting, and such behaviors may relieve this feeling.
Doctors diagnose the disorder when people pick at or bite parts of their body enough to cause damage, try to stop their behavior and cannot, and are significantly distressed by their behavior or function less well because of it.
Cognitive-behavioral therapy that specifically focuses on body-focused repetitive behavior disorder and certain antidepressants or N-acetylcysteine may help lessen symptoms.
Body-focused repetitive behavior disorder is classified as an obsessive-compulsive and related disorder Obsessive-Compulsive Disorder (OCD) Obsessive-compulsive disorder is characterized by obsessions, compulsions, or both. Obsessions are recurring, persistent, unwanted, anxiety-provoking, intrusive ideas, images, or urges. Compulsions... read more . People with body-focused repetitive behavior disorder compulsively pick, pull, or tug at one or more parts of their body. They may bite their nails or lips, chew their cheeks, or pick at their nails.
Hair pulling Hair-Pulling Disorder (Trichotillomania) In hair-pulling disorder, people repeatedly pull their hair out, resulting in hair loss. People with hair-pulling disorder may feel tense or anxious just before they pull their hair out, and... read more 
and skin picking Skin-Picking (Excoriation) Disorder In skin-picking disorder, people repeatedly pick at their skin, damaging it. People with skin-picking disorder may feel tense or anxious just before they do it, and skin picking may relieve... read more are also body-focused repetitive behaviors. They are classified as separate disorders in DSM-5, but as subheadings of body-focused repetitive behavior disorder in ICD-11.
Symptoms
Some people with body-focused repetitive behavior disorder do these activities somewhat automatically—without thinking about it. Others are more conscious of the activity.
People do not engage in these behaviors because they are obsessed with or concerned about their appearance (as occurs in body dysmorphic disorder Body Dysmorphic Disorder In body dysmorphic disorder, a preoccupation with one or more nonexistent or slight defects in appearance results in significant distress and/or impairs functioning. People typically spend hours... read more ). However, they may feel tense or anxious just before they do them, and doing them may relieve that feeling. Afterward, they often have a sense of gratification. People may also be distressed by their loss of control and repeatedly try to stop the activity or do it less often, but they cannot.
If people bite or pick at their nails a lot, the nails may become deformed. Grooves and ridges may develop in the nails, or blood may collect under the nail, producing a purple-black spot.
Diagnosis
A doctor's evaluation, based on specific diagnostic criteria
Doctors diagnose body-focused repetitive behavior disorder based on symptoms:
Picking at or otherwise manipulating a body part, sometimes resulting in bodily damage
Repeatedly trying to reduce or stop the activity
Feeling greatly distressed or being less able to function because of the activity
Treatment
Drugs
Cognitive-behavioral therapy
Treatment of body-focused repetitive behavior disorder may include drugs, such as selective serotonin reuptake inhibitor antidepressants Selective serotonin reuptake inhibitors (SSRIs) Agomelatine, a new type of antidepressant, is a possible treatment for major depressive episodes. Several types of drugs can be used to treat depression: Selective serotonin reuptake inhibitors... read more and N-acetylcysteine, and cognitive-behavioral therapy.
Cognitive-behavioral therapy that specifically focuses on this disorder may lessen symptoms. The most highly recommended type of cognitive-behavioral therapy is habit reversal therapy. For this therapy, people are taught to do the following:
Become more aware of what they are doing
Identify situations that trigger the activity
Use strategies to help them stop themselves from doing the activity—for example, by substituting a different activity (such as clenching their fist, knitting, or sitting on their hands) for it
