Introduction

Billy Milligan, often referred to as the “Campus Rapist,” became one of the most famous cases of multiple personality disorder (now called dissociative identity disorder, or DID) in American criminal history. In the late 1970s, Milligan was arrested for a series of armed robberies and rapes committed on the Ohio State University campus. What made his case extraordinary was his diagnosis of DID, which revealed that different personalities within him were responsible for his crimes. This raised unprecedented legal and psychological questions about criminal responsibility, mental illness, and the justice system. This paper will examine Billy Milligan’s background, the motives and actions of his alternate personalities, the investigation and trial, and the psychological complexities surrounding his crimes.

Background

Billy Milligan was born on February 14, 1955, in Miami Beach, Florida, to a troubled and unstable family. His father reportedly abandoned him at a young age, and his mother subjected him to abuse and neglect. Milligan suffered physical abuse, exposure to violence, and chronic trauma during his formative years, factors that psychologists later identified as contributing to the development of dissociative identity disorder.
As a teenager, Milligan began experiencing severe mental health issues, including hallucinations, blackouts, and episodes of amnesia. Despite these challenges, he was described as intelligent and articulate. By the time of his adulthood, Milligan had developed multiple distinct personalities, each with its own traits, memories, and behaviors, which played a crucial role in his later criminal actions.

Motives

The motives behind Milligan’s criminal acts were complex and intertwined with his multiple personalities. Some of his personalities were violent and impulsive, committing crimes without Milligan’s conscious awareness, while others were unaware of these actions or served as protectors. The violent crimes, including rape and robbery, were carried out by personalities that were aggressive, manipulative, and predatory.
From a psychological perspective, Milligan’s actions highlight how severe trauma and dissociation can fragment a person’s identity, resulting in alternate selves that act independently and, in some cases, dangerously. While the legal system struggled to reconcile his mental condition with criminal responsibility, Milligan’s case became a landmark in understanding DID and its implications for accountability.

Methods

Milligan’s methods varied depending on which personality was in control. In the 1970s, during his crimes at Ohio State University, the violent personalities carried out armed robberies and sexual assaults, often targeting students. He would approach victims with a weapon, force compliance, and commit assault. Other personalities reportedly had no knowledge of these acts and were entirely unaware of the crimes committed in their absence.
This dissociative behavior complicated the investigation, as Milligan himself could not recall the attacks. Witness accounts, forensic evidence, and reports from victims eventually linked the crimes to him, though the involvement of multiple personalities added layers of complexity to understanding his culpability.

Caught

Billy Milligan was apprehended in 1977 following an investigation into the robberies and assaults at Ohio State University. Police linked the crimes to Milligan through eyewitness descriptions, physical evidence, and suspicious behavior. Upon arrest, Milligan exhibited signs of severe mental disturbance, prompting psychological evaluation.
During assessment, clinicians discovered the presence of at least 24 distinct personalities, including violent, protective, and childlike identities. This groundbreaking diagnosis revealed that some personalities had committed the violent acts while the primary personality, Billy, had no conscious awareness of the crimes.

Court and Sentencing

Milligan’s case set a precedent in the legal system. His attorneys argued that his multiple personalities rendered him legally insane and incapable of being held fully responsible for his actions. In 1978, a court accepted this argument, making him the first person in U.S. history to be acquitted of major felonies on the grounds of dissociative identity disorder.
Instead of prison, Milligan was committed to mental health institutions for treatment and evaluation. Over the years, he underwent therapy aimed at integrating his personalities and managing his condition. He was released in 1988, though he lived under continued scrutiny and media attention until his death in 2014.

Conclusion

Billy Milligan’s case is a landmark in criminal psychology, highlighting the complexities of mental illness and its interaction with criminal behavior. His multiple personalities demonstrated how severe trauma can fracture identity, leading to behaviors that challenge conventional notions of culpability.
Psychologically, the Milligan case raises profound questions about free will, accountability, and the capacity for individuals to commit crimes without conscious intent. While controversial, his story continues to influence forensic psychology, legal practice, and public understanding of dissociative identity disorder, marking a unique intersection of crime and mental health.