Dangerous Minds: The Mental Illnesses of Infamous Criminals

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Mental illnesses have been found in some of the U.S.’s most loathsome killers throughout history, but it’s important to note that most people suffering from these illnesses do not commit any violent offenses. These instances of mental disorders represent only a small fraction of people diagnosed and the majority of people afflicted do not engage in criminal activity, especially if given proper treatment and social support.

In the wake of a violent assault, robbery, or murder, forensic psychologists typically examine the mental correlates of criminality. In order to get to the root of a behavior, these justice system professionals will often ask such questions as:

  • Did the accused have a troubled childhood?
  • Does (s)he exhibit empathy for others?
  • Does (s)he self-medicate with drugs or alcohol?

Not surprisingly, many criminals have been diagnosed with mental illnesses and may be suffering from co-occurring substance abuse.

So what are some of the most common psychological disorders associated with history’s most infamous American criminals—serial killers and terrorists in particular?


According to WebMD, schizophrenia—a wide-ranging (and often misdiagnosed) mental illness—lists symptoms ranging from hallucination and delusions to emotional flatness and catatonia. It is one of the most common mental disorders diagnosed among criminals, especially serial killers:

  • David Berkowitz, better known as the “Son of Sam” killed six people in the 1970s claiming that his neighbor’s dog had told him to do it. He was diagnosed with paranoid schizophrenia.
  • Ed Gein, gruesome inspiration for fiction’s Norman Bates, Buffalo Bill, and Leatherface, murdered and mutilated his victims often keeping grisly “trophies.”
  • Richard Chase—”the vampire of Sacramento”—killed six people in California and drank their blood.
  • David Gonzalez killed four people in 2004 and claimed he’d been inspired by “Nightmare on Elm Street.”
  • Jared Lee Loughner, convicted of killing six people and wounding 13 including U.S. Representative Gabrielle Giffords in 2011, was diagnosed with paranoid schizophrenia.
  • James Eagan Holmes, currently on trial for the 2012 “Batman murders” in Aurora, has been diagnosed with schizophrenia by 20 doctors.

Borderline personality disorder

This disease is characterized by impulsive behaviors, intense mood swings, feelings of low self worth, and problems in interpersonal relationships (WebMD). It has also been diagnosed among some of the U.S.’s most notorious serial killers. Interestingly, this seems more common among female criminals:

  • Aileen Wuornos, the woman who inspired the 2003 film “Monster” starring Charlize Theron, confessed to seven murders in Florida. She was also diagnosed with antisocial personality disorder.
  • Jeffrey Dahmer, also known as the “Milwaukee Cannibal,” killed seventeen boys and men between 1978 and 1991. He also struggled with heavy alcohol abuse.
  • Kristen H. Gilbert killed four patients at a Northampton, Virginia hospital where she worked as a nurse by administering fatal doses of epinephrine to induce cardiac arrest.

Antisocial personality disorder

Known in the past as “psychopathy,” this mental disorder is characterized by a total disregard of the feelings of others. People with APD may lie, act out violently, or break the law and show no remorse. WebMD reports that while APD only affects 0.6% of the population, it may affect up to 47% of male inmates and 21% of female inmates. It’s also been diagnosed among three of the most ruthless American serial killers:

  • Ted Bundy, an infamous killer and necrophile, confessed to 30 murders in the 1970s.
  • John Wayne Gacy, known as the “Killer Clown,” raped and killed 33 boys and young men in the 1970s.
  • Charles Manson, leader of the “Manson Family” cult and mastermind behind the 1969 murders at the home of Sharon Tate, was diagnosed with antisocial personality disorder.

While these three disorders are commonly seen among violent criminals, there have also been a number of killers whom were never diagnosed with mental illnesses. For example, Dean Corll, also known as the “Candy Man” or the “Pied Piper,” kidnapped, raped, and killed 28 boys between 1970 and 1973 in Houston, Texas and was never diagnosed. Additionally, Timothy McVeigh, the Oklahoma City bomber of 1995, killed 168 people and injured over 600, and yet he too never was given a mental illness diagnosis.

Still, mental illness in prison populations and among criminals continues to be an issue in the United States today. In order to decrease prison recidivism and rates of violent crime, it’s essential that rehabilitative services and mental illness treatments be improved in this dangerous yet vulnerable population.