Body dysmorphic disorder (BDD) is a distressing form of self-consciousness. Those with it focus intensely on their appearance. They look normal, yet they are preoccupied. They think they look defective.

Many BDD patients know their worry is unreasonable. But some have no idea that their concerns are not realistic.

People with BDD may constantly check themselves in the mirror. They may seek cosmetic surgery to repair perceived defects.

Many BDD patients are ashamed of their appearance. They avoid public places. Shame can play havoc with their relationships. Work may become impossible.

Some features of the illness look like depression. Other features seem to suggest obsessive-compulsive disorder. The refusal to leave home looks like social phobia. Many with the disorder have alcohol or drug related problems.

We don’t yet know what causes BDD. Rates may be higher in the United States. Our culture favors a slim, muscular and athletic look. Technology makes photos of actors and models look perfect. That sets an unnaturally high bar for appearance.

Brain function may be altered in BDD patients. People with BDD may have a unique way of processing visual information. They seem to focus on details rather than larger features. In other words, they lose the forest and concentrate too much on the trees.

BDD patients often don’t see the problem as a mental one. They may not recognize that their body beliefs are mistaken. That makes it hard for them to seek treatment.

The first priority is to avoid unnecessary cosmetic surgeries. Medicine (for example, antidepressants) may help. Cognitive behavior therapy can help treat milder forms of the illness. Your friend may also benefit from your patience, support and understanding.