Jon is a Welsh-born investigative journalist and author who explores the madness industry with a blend of skepticism and anxiety. He serves as an everyman proxy for the reader, questioning the influence of psychiatric labels across prisons, corporate boardrooms, and media. His own neuroses and self-doubt frequently surface as he attempts to separate typical behavior from clinical pathology.

Robert is a Canadian psychologist and the creator of the Psychopathy Checklist-Revised (PCL-R), the dominant tool for assessing psychopathy. An emeritus professor at the University of British Columbia, he developed his criteria based on early experiments with prison inmates, identifying key neurological and behavioral deficits. He possesses immense institutional authority, though his methods sometimes raise ethical questions about diagnostic overreach.

Tony is a well-dressed man in his late twenties held in Broadmoor's Dangerous and Severe Personality Disorder unit. He originally fakes mental illness at age 17 to avoid a prison sentence, only to be permanently labeled a psychopath by the psychiatric establishment. He struggles to prove his sanity to a system that views his every action, whether cooperative or rebellious, as evidence of his pathology.

Robert is a prominent American psychiatrist at Columbia University and the lead architect of the DSM-III. Driven by his mother's negative experiences with psychoanalysis, he shifts the psychiatric field toward symptom-based checklists. He is deeply interested in classifying people, though his rigorous standardization inadvertently contributes to the rapid expansion of psychiatric diagnoses.

Al is a corporate executive nicknamed Chainsaw Al who is famous for orchestrating ruthless mass layoffs at companies like Sunbeam. He defends his aggressive downsizing strategies and frames his lack of remorse as a necessary business virtue. He serves as a real-world example of how traits associated with psychopathy are often rewarded in capitalist environments.

Emmanuel is the imprisoned founder of a Haitian paramilitary death squad known as FRAPH. Initially appearing charming and vulnerable, he eventually reveals that his desire to be liked is a calculated strategy for manipulation. He provides Jon with a chilling demonstration of performative emotion and predatory behavior.

Allen is an American psychiatrist and former chair at Duke University who served as the task-force chair for the DSM-IV. He transforms into a vocal critic of diagnostic inflation and the over-medicalization of typical behavior. He advocates for clinical restraint, warning that expanding diagnostic criteria frequently leads to false epidemics and widespread misdiagnosis.

Elliott is a Canadian psychiatrist who pioneers radical therapeutic communities for violent offenders at the Oak Ridge facility. He operates with intense idealism, believing he can cure psychopathy using LSD-fueled marathon nude psychotherapy sessions called the Total Encounter Capsule. His visionary methods ultimately result in disastrous consequences and high recidivism rates.

Brian is a Scientologist working for the Citizens Commission on Human Rights. He disbelieves in psychiatric diagnoses and actively seeks to debunk them, guiding Jon toward Tony's case at Broadmoor.

Anthony is a professor and the chief clinician overseeing Tony's case at Broadmoor. He maintains that Tony possesses psychopathic traits but occasionally criticizes the rigid application of psychiatric checklists, recognizing that individuals can have both atypical and endearing qualities.

David is a former MI5 officer and whistleblower who descends into promoting conspiracy theories, eventually declaring himself the Messiah. His trajectory illustrates the media's selective appetite for entertaining forms of madness.

David is an American psychologist at Stanford University whose landmark On Being Sane in Insane Places experiment exposes the unreliability of psychiatric diagnosis. By sending healthy individuals into mental hospitals, he demonstrates how clinical labels permanently distort the perception of everyday behavior.

Gary is a US-trained forensic psychiatrist who succeeds Elliott Barker at Oak Ridge. He represents an escalation of therapeutic experimentalism, introducing mass LSD trips and chanting sessions for violent offenders. He approaches his patients as searching souls rather than malicious figures, but his lack of traditional scientific rigor leads to his eventual dismissal.

L. Ron Hubbard is the American founder of Scientology who establishes the Citizens Commission on Human Rights (CCHR) to expose psychiatric abuses. He views psychiatry as a corrupt industry rivaling his own authority over the human mind. His legacy introduces a complex anti-psychiatry counter-narrative to Jon's investigation.

Deborah is a neurologist who contacts Jon regarding a mysterious book sent anonymously to academics worldwide. She attempts to decode the cryptic text, assuming it is a brilliant puzzle.

Petter is a Swedish psychiatrist and translator responsible for the cryptic book Being or Nothingness. He possesses an obsessive mind that generates international confusion among academics through his mailing project.

Essi is a psychologist who studies psychopaths. She introduces Jon to the formal diagnostic tools used in the field, helping him contextualize Tony's clinical evaluation.

Adam is a documentary filmmaker and friend of Jon. He challenges Jon's investigative methods, comparing journalists to medieval monks who stitch together extreme behaviors while ignoring the complex reality of their subjects.

Charlotte is a former daytime television guest booker who screens potential reality show participants based on their psychiatric medications. She actively seeks out individuals who are just mad enough to provide entertainment without being completely unstable.

Paul is a once-celebrated criminal profiler whose career collapses after he directs a disastrous, deceptive undercover operation against an innocent suspect. He relies heavily on rigid psychological templates, ignoring empirical reality when it contradicts his profiles.

Colin is a local man who becomes the target of a months-long undercover police sting based on a psychological profile. Despite intense manipulation and fabricated stories of ritual violence, he maintains his innocence.

Rachel is an advertising professional who survives the July 7 bombings in London. She faces severe online harassment from conspiracy theorists who refuse to believe her firsthand accounts of the attack.

Peter is a notorious child-killer who participates in the Total Encounter Capsule therapy program at Oak Ridge. He ultimately uses the empathy techniques he learns to manipulate his doctors, murdering a fellow patient shortly after his first supervised release.

Judy is Al Dunlap's wife, sharing his opulent estate. Her long, stable marriage to him serves as a complicating factor in Jon's attempts to perfectly map psychopathic traits onto her husband.

Troy is Al Dunlap's estranged son. He is noticeably absent from the family photographs in the Dunlap mansion, representing the fractured personal relationships resulting from his father's aggressive personality.

Deleese is a woman selected for a television makeover show whose family is coached by producers to criticize her appearance. When she is abruptly cut from the show, she sinks into a deep depression, illustrating the severe human cost of exploitative media practices.

Kellie is Deleese's sister who suffers from bipolar disorder. After participating in a reality show segment that heavily criticizes her sister, she is overwhelmed by guilt, demonstrating the tragic consequences of manufacturing drama for entertainment.

Joseph is a doctor at Massachusetts General Hospital who drives the childhood bipolar epidemic. He promotes powerful medications for young children while allegedly receiving funding from pharmaceutical companies.

Kayoko is a doctor and a follower of Joseph Biederman's diagnostic approach. She diagnoses three-year-old Rebecca Riley with bipolar disorder and prescribes the heavy medication regimen that leads to her death.

Rebecca is a four-year-old girl who is diagnosed with childhood bipolar disorder at age three. She is prescribed a heavy regimen of unapproved psychiatric medications, ultimately dying from an overdose, which highlights the fatal risks of diagnostic expansion.

Bryna is a mother in Rhode Island whose son is misdiagnosed with bipolar disorder. She shares her experiences with Jon, detailing the heavy medications her children endure due to expanding psychiatric criteria.

Matt is Bryna's son who is diagnosed with bipolar disorder at four years old after a simple tantrum. He spends a decade taking numerous psychiatric medications due to this aggressive diagnostic labeling.

David is a child psychiatrist who speaks with Jon about the misdiagnosis of pediatric bipolar disorder. He clarifies that many heavily medicated children actually have less severe atypicalities, warning of the lifelong consequences of incorrect labeling.

Levi is a student at Indiana University who claims to find copies of the cryptic book Being or Nothingness under a railway bridge. His involvement briefly leads Jon down a speculative path before his story is verified.

Douglas is a prominent academic and computer scientist who receives the anonymous book Being or Nothingness. He dismisses the project as the work of a crackpot, steering Jon toward the true creator.