First, provide a definition of Personality Disorder using your own words

First, provide a definition of Personality Disorder using your own words.

Second, read the article 'Personality Disorders."

Personality disorders are a group of mental illnesses. They are unique in that they make having healthy personal relationships for the sufferer difficult. The abstract of this article provides a great description and definition of "personality disorder"

Please provide this definition and discuss when these disorders begin to typically appear and what the problems/limitations are.