Diana Reid

Diana "Diane" Reid is the mother of Spencer Reid and a recurring character of Criminal Minds.

Background
Like her son, Diana is a genius, although her IQ is never mentioned. She raised Spencer as a single mother after her husband left her due to her schizophrenia (among other things). She read to Spencer often, enforcing his already growing intelligence. From her, Spencer learned that the best way to learn is to do "the research" on your own. Through the years, the reading time began to take place in her bedroom, where she spent most of her time on medication. When Spencer was eighteen, he made the difficult decision to finally have her committed. She now resides in the Bennington Sanitarium, where she receives a letter from her son every day.

Part 1
Diana is first seen sitting in the sanitarium as Spencer watches. However, before he can come up to her, he is forced to get back to the BAU to assist on the latest case. She isn't seen for the rest of the episode.

Part 2
When Spencer realizes that the unsub they are tracking down was once institutionalized in the sanitarium Diana is currently residing in, even during her stay, he fears that she might be the next victim and gets two agents to retrieve her from the sanitarium. Unfortunately, she is taken to Quantico via plane, in spite of her fear of flying. At the BAU headquarters, she and Spencer engage in their first conversation in years, during which Diana briefly expresses her distaste at not having seen her son in such a long period of time. When Spencer shows her a videotape of the unsub speaking, Diana instantly recognizes the voice and identifies him as Randall Garner.

When the BAU attempt to locate Randall's current address, Diana shows the team a photo of a medieval-styled mansion that was sent to her, with the address of said mansion written at the back. After Randall blows himself up upon being confronted by Spencer and a hostage of his is rescued, Spencer arrives back at the BAU headquarters to find Diana in the middle of a hallucination, believing that she is teaching a lecture in her class. Spencer goes along with his mother, asking if he can be a part of the lecture. When Diana asks if he read the material, he replies that it was read to him, to which she smiles and replies that it is the best way to learn it. Spencer and Diana are then both seen on the BAU's private plane as it heads back to Las Vegas, with Spencer comforting a fearful Diana by reading a book to her.

Revelations
After being drugged with dilaudid by Tobias Hankel, Spencer is rendered unconscious by the drug and experiences several flashbacks regarding Diana and, at one point, William.

The Instincts
While investigating a case in Las Vegas, Spencer has a dream in which he is among those attending the funeral of the recently-murdered Riley Jenkins. Diana and a young Spencer appear, the former encouraging him to focus, causing him to wake up. While investigating Riley's murder, Spencer decides to interrogate Diana, but when he asks her of Riley, she dismisses the fact of him knowing Riley, stating that Riley was a figment of Spencer's childhood imagination. However, Spencer continues the investigation after having a dream depicting William discarding Riley's corpse.

Memoriam
After finding out the identity of Riley's murderer, Gary Michaels, Diana and William both come forward to him and tell him of how Diana became suspicious of Gary when he began stalking Spencer as a child. Diana alerted Riley's father Lou, who was distraught at the loss of his son, and after he discovers Gary's status as a pedophile, he and Diana arrived at Gary's residence. Diana watched Lou enter the house with a baseball bat at hand, and after a while, she too entered the house to find Lou standing over a dead Gary. Managing to get some of Gary's blood on her clothes, Diana and Lou both fled the scene and the former informed William. Fearing that Diana might be charged of being Lou's accomplice, he disposed her bloody clothes and Gary's murder was ultimately left unsolved, but the both of them were emotionally scarred by this and this resulted in their separation. Lou is presumably arrested afterwards for killing Gary, while Diana and William continue on separately with their lives, the resultant pressure from keeping their secret having been lifted.

Persuasion
While she didn't physically appear in the episode, it seemed that Diana's mental condition was beginning to improve, as she wasn't signed into the sanitarium as frequently and was actually allowed to have a supervised vacation to the Grand Canyon during the BAU's current case. By the end of the episode, Diana sent Spencer a number of postcards and a collectible miniature of the Grand Canyon.

Target Rich
Like in Season Nine, Diana doesn't physically appear in the episode, but she is the topic of a subplot. Spencer revealed to JJ that Diana's mental condition had begun to rapidly deteriorate, and sanitarium employees had to restrain her at some points. This worried him to the point where he began considering dilaudid again. JJ tells him to call her, and he says he will once the team finishes the current case. By the end of the episode, Spencer does indeed call her, and he asks if it would be okay for him to visit her for a few days.

Entropy
While being held hostage by Cat Adams, Reid is forced to recount why he took a leave of absence to visit his mother. Reid then proceeds to tell Cat how Diana has schizophrenia and the new medication the doctors have prescribed recently hadn't been working. However, Reid also confesses to Cat how, when he visited Diana, she didn't immediately recognize him. Reid had Diana tested and the doctors diagnosed her as having early-onset dementia and would most likely progress into having Alzheimer's disease. A younger Diana then appeared in a flashback, pushing Reid on the swing of a park.

Appearances

 * Season One
 * The Fisher King, part 1
 * Season Two
 * The Fisher King, part 2
 * Revelations
 * Season Four
 * The Instincts
 * Memoriam
 * Season Eleven
 * Entropy