With factitious disorder, the individual behaves as if he or she has a physical or mental illness when, in fact, he or she has intentionally produced his or her symptoms. Individuals with factitious disorders purposely create or embellish symptoms of an illness in many ways. These individuals may falsify or mimic symptoms of an illness, injure themselves to bring on symptoms, or manipulate laboratory and diagnostic tests (such as purposefully contaminating urine or blood samples).

These people have an internal desire to be seen as weak, ill or injured. However, in many cases there is no intention of gaining any financial benefit from this behavior. These individuals often undergo unnecessary painful and very risky medical tests and procedures in order to obtain empathy and attention which is normally given to sick people.

Most people with factitious disorder also suffer from other mental disorders and in particular personally disorders. These people often have different thoughts and behaviors and clearly stand apart from the norm. They also tend to have labile moods, be impulsive, angry and passive. They also have a lack of ability to cope with problems and most have had very poor interpersonal relationships.
There are a variety of factitious disorders- some may mimic a mental illness and others may mimic a physical disorder like a heart attack. There is also factitious disorder by-proxy where the individual fabricates symptoms of an illness in another person, especially a child.

Warning signs of a factitious disorder include:
- Inconsistent medical history with unclear symptoms
- Dramatic medical tales with predictable relapses
- Extensive medical knowledge and being well-read on the topic
- Evidence of many scars
- Continuing to complain of symptoms despite negative tests
- Being very willing to undergo tests and surgery for minimal indications
- Seeking doctors in different cities and never being willing to take family members to meet health professionals or vice versa

No one knows the origin of factitious disorder but both the environment and genetic factors seem to play a role. There are no reliable statistics on this disorder because most people visit many doctors and are also habitual lairs.

The diagnosis of factitious disorder is difficult and is only made after an exhaustive work up reveals no real medical problem. The first goal of treatment is stopping the person from abusing medical resources. Next, the aim is to ensure safety and protection of any real victims like children. The treatment for the individual resolves around stabilizing the psychosocial issues that are causing the problem. Psychotherapy may help change thinking and behavior. Medications are only used to treat secondary depression or anxiety. The prognosis of people with factitious depends on the duration of the illness. For those with short term problems, the prognosis is good but for those with long term problem, the prognosis is poor. Most people continue their behavior and deny that they are faking symptoms. Some eventually end up with real medical problems which are never taken seriously. Because the cause of factitious disorder is not known, prevention is not possible.

Source:
http://emedicine.medscape.com/article/291304-overview