Could bitterness so powerful that it adversely affects the ability to function much beyond sitting and brooding over your pain actually be considered a mental illness?

The American Psychiatric Association discussed just that at their annual meeting in San Francisco last week, according to the LA Times.

The disorder, named post-traumatic embitterment disorder, was named by Dr Michael Linden, a German psychiatrist. The name is deliberately evocative of post-traumatic stress disorder, after which it is modeled because it too is a response to a trauma that endures. People with PTSD are left fearful and anxious. Embittered people are left seething for revenge.

"They feel the world has treated them unfairly. It's one step more complex than anger. They're angry plus helpless," says Dr Linden.

Linden says there are only a handful of studies on the condition, and more research is needed to identify who can be helped. Linden says one estimate is that 1% to 2% of the population is embittered.

Psychiatrists working to identify new psychiatric conditions are on the cutting edge of psychology, but part of a larger community of mental health professionals. The Bureau of Labor Statistics estimates there will be almost 200,000 psychologists employed by 2016.