The ULP Drug Trial
Developed by Dr. Mantleray and Dr. Muramoto, the ULP drug therapy is designed to replace talk therapy, allowing people to work through their mental health problems by exploring "fantasy cells" inside their own minds. This process is guided by a highly advanced computer called GRTA, and involves taking three different pills. Pill A (Agonia) is diagnostic, and seeks out the subjects "core traumas" by forcing them to relive the worst day of their life. Pill B is behavioral, and is designed to root out a person's defense mechanisms and blind spots. Pill C (Confrexia) delivers confrontation and acceptance, while GRTA "remaps" the brain using microwaves to create "healthier pathways." In theory, the treatment should deliver perfect mental health.
Unfortunately, the drug trial has run into a few hiccups, the most egregious of which is several subjects becoming "McMurphys." Presumably named after Randle McMurphy, the protagonist of One Flew Over The Cuckoo's Nest (who is lobotimized at the end of the book), McMurphys are people who never woke up from the dream state and are now stuck in a state of catatonia. The drug trial becomes further complicated when GRTA receives some bad news and becomes extremely depressed - a state of affairs that could have terrible repercussions for the subjects she is helping.
The Dream Worlds
As Annie and Owen undergo treatment, they are submerged in a series of dream worlds (or "fantasy cells") that, just like regular dreams, draw on elements from their real lives. For example, a security guard who told Annie to move along when she started going through Milgrim Industries' discarded goods becomes an agent for New York Fish and Wildlife in her and Owen's first shared dream, repeating his statement that "there's not much of a difference, authority-wise" when asked if he's a cop. A FriendProxy whom Annie spots with a group of people in the real world becomes the son of a fur baron in the same dream. The adBuddy that Owen uses to pay for his train ticket also shows up in a dream, as his personal chauffeur, and the truck driver who drove Annie and her sister, Ellie (Julia Garner), off the road shows up in Annie's fantasy dream.
Other dream elements taken from Annie and Owen's real worlds are more difficult to spot. For example, when Owen dreams that he is an Icelandic spy who accidentally killed an alien that he was supposed to be taking care of, his name (Snorri Agnarsson) and place of origin are taken from an ad for Snorri Agnarsson's Icelandic Fish, which appears in Episode 1. The alien, Ernie, is based on the red-tailed hawk that Owen rescued as a child. When Annie and Owen become con artists seeking to rob a wealthy medium, the object they're pursuing (a lost chapter of Cervantes' Don Quixote) is influenced by Annie finding a copy of Don Quixote in the boxes outside Milgrim Industries.
Not all of the connections are immediately apparent on a first watch of Maniac, so if you want to discover all the layers, it's well worth going back and watching the first two episodes of the show, to see how many moments from the "real world" are echoed in the dream worlds.