Delusions.

CNN.com:

"SANTA FE, New Mexico (AP) -- A state judge has lifted a restraining order granted to a Santa Fe woman who accused talk-show host David Letterman of using coded words to show that he wanted to marry her and train her as his co-host...

Nestler's application for a restraining order was accompanied by a six-page typed letter in which she said Letterman used code words, gestures and 'eye expressions' to convey his desires for her.

She wrote that she began sending Letterman 'thoughts of love' after his show began in 1993, and that he responded in code words and gestures, asking her to come east.

Nestler said Letterman asked her to be his wife during a televised 'teaser' for his show by saying, 'Marry me, Oprah.' Her letter said Oprah was the first of many code names for her and that the coded vocabulary increased and changed with time."

Dr. Neubauer explains:

The quick definition of a delusion is a fixed false belief. It’s fixed because the person can’t be convinced otherwise, even though it’s obviously false to others...Delusions, while untrue, may be entirely plausible or they may be quite bizarre.

Some people have particular types of delusions, such as paranoid, persecutory, religious, or grandiose. People may believe that others control their thoughts and actions or that everyone around them can hear their thoughts.

Delusions, along with hallucinations and disorganized speech, are a psychotic symptom characteristic of schizophrenia and related psychiatric disorders. Usually, these symptoms are transient or are controlled with medications."

And from Schizophrenia.com:

Arguing with a delusion only leads to further mistrust or anger. The beliefs are tenaciously held, against all reason, & they are characteristically not shared beliefs. They are held only by the person himself & by no one else.

Families & friends must first realize that delusions are a result of illness & not stubbornness or stupidity. Although fixed delusions can be irritating, emotional reactions should be avoided, as should taunts or threats...