In most of season five, Amanda Righetti (Grace Van Pelt) was pregnant. Since it didn't fit in with the story line, she can only be seen sitting behind a computer or in dark shadows in almost every scene, and doesn't go into the field.
In every close-up shot you can see that Patrick Jane has dilated pupils. That is, as he himself says about other people he encounters, a sign of shock or hypnosis.
In most episodes the victim or perpetrator has a name indicative of his true character. Examples: McTyranny, Quick, Just, Unjust.
Owain Yeoman is in fact Welsh; he puts on the American accent he uses, which even fooled the other cast members, as he always stayed in character, even when the cameras weren't rolling.
The concept for the show--a man who is hyper-observant and fakes being a psychic) is the same as the series Psych (2006), which aired two years earlier.
Patrick Jane's personal car is an early 1970s model Citroën DS, manufactured in France from 1955-75, and sold in the U.S. from 1956-72. The DS was the first mass production car to offer hydropneumatic self-leveling suspension with an option for the driver to manually raise or lower the chassis at the push of a button.
An outdated nickname for Patrick is Pink, and 'Jane' is a female version of John, making Patrick (Pink) Jane a variation of Red John.
The names of several characters are taken from the 1960s TV series The Fugitive. "Red John" is taken from the name of the one-armed man: fRED JOHNson. Kimball Cho gets his name from Dr. Richard Kimble. Madeleine Hightower gets her name from the high tower in the ending of "The Fugitive".
Lapsang souchong, the tea that Patrick Jane drinks, is a type of black tea originating from China. Black tea is called "hong cha" in Chinese, which translates literally to "red tea".
At the end of the pilot episode Jane brings the team donuts to celebrate closing the case. The case-closing celebration becomes a CBI tradition, with the food of choice changing to pizza.
Frequently there is talk of putting out a "BOLO" on a suspect or missing person. This is an acronym for "Be On The Lookout", a term synonymous to an APB--All Points Bulletin--stating all the specifics of the person(s) being searched for.
It's mentioned that Lisbon is from Chicago, which actually is Robin Tunney's hometown.
Red John's right-hand man, Oscar Cordero (Cor-DER-o) and his right-hand woman, Rebecca Anderson (an-DER-son) are the only two characters ever on The Mentalist with the word "red" frontwards or backwards in their name except for the three characters named 'Xander,' who were named after the actor who played Red john.
Charlotte Jane, the daughter of Patrick Jane, received her name from producer Bruno Heller's father, who wrote Hush, Hush, Sweet CHARLOTTE, and What ever Happened to Baby JANE.
The first seven minutes of the opening of The Mentalist has Jane living vicariously through a character named June who kills the man who killed her daughter, just as he would like to do.