Could John Mark Karr Have Lying Disorder?

Karr may suffer from factitious disorder, according to Dr. Marc Feldman, a psychiatrist who co-authored the books "Patient or Pretender: Inside the Strange World of Factitious Disorders," "The Spectrum of Factitious Disorders," and "Stranger Than Fiction: When Our Minds Betray Us." The condition leads someone to construct a false reality — sometimes to the extent that they begin to believe their own lies.