When you hear the phrase 10 infamous criminals, you probably picture outlaws who got away with murder, but these ten individuals actually slipped past the gallows or the cell block by convincing a jury they weren’t responsible for their own actions. The insanity defense is a legal oddity—used in less than one percent of cases with a success rate hovering around a quarter—but when it works, it rewrites history. Below, we explore each headline‑grabbing case, from royal assassination attempts to Hollywood‑inspired presidential attacks.
10 Roderick Maclean
Queen Victoria, famed for surviving eight assassination attempts, faced her most eccentric challenger in Roderick Maclean. The disgruntled poet‑turned‑gunman believed the monarch despised his verses, prompting him to open fire on her at Windsor on March 2, 1882. His first bullet missed, and two schoolboys tackled him before he could fire a second shot.
Charged with high treason—a capital offense—Maclean had already been certified insane by medical examiners. The jury, after a brief deliberation, returned a verdict of “not guilty, but insane,” sparing him the hangman’s noose. He spent the remainder of his days at Broadmoor Asylum, and his case helped spur the 1883 Trial of Lunatics Act, which later altered the standard verdict to “guilty, but insane.”
9 Jeffrey Arenburg
In August 1995, Canadian television station CJOH became the target of a paranoid schizophrenic named Jeffrey Arenburg, who believed broadcasters were beaming thoughts into his mind. Armed with a .22‑caliber rifle, Arenburg entered the station and fatally shot sports anchor Brian Smith, a victim of pure circumstance.
Although charged with first‑degree murder, a jury found Arenburg “not criminally responsible” because of his mental disorder. He was committed to a psychiatric facility for a decade before his eventual release, illustrating how the insanity plea can redirect a life from prison to treatment.
8 George Roden
The Branch Davidians’ infamous 1993 siege is well‑known, yet few remember that David Koresh wrested control from his predecessor, George Roden. The son of founder Benjamin Roden, George lost the leadership battle after a 1987 shootout and later saw the property seized for unpaid taxes.
Two years after his ouster, Roden murdered his roommate, Wayman Dale Adair, convinced that Koresh had dispatched him. Declared not guilty by reason of insanity, Roden spent his final years in various mental hospitals. In 1998, he escaped Big Spring State Hospital only to be found dead on a roadside, likely from a heart attack.
7 James Hadfield
James Hadfield, a former British dragoon, suffered severe head injuries in the French wars, which later manifested as delusions of grandeur. He fancied himself the true King George, the biblical Adam, and even a “Supreme Being.” Believing his own death would save the world, he attempted to kill King George III at the Theatre Royal on May 15, 1800.
Hadfield’s shot missed, and the crowd quickly subdued him. Renowned lawyer Thomas Erskine successfully argued that Hadfield was insane, resulting in a permanent confinement at Bedlam rather than execution. This case helped cement the legal principle that mental illness could absolve a defendant of criminal responsibility.
6 Izola Curry
Before Martin Luther King Jr. was assassinated, a different tragedy nearly unfolded. Izola Curry, a Black woman diagnosed with paranoid schizophrenia, harbored delusional beliefs that civil‑rights leaders were Communist conspirators. On September 20, 1958, she approached King at a Harlem book signing and thrust a seven‑inch letter opener into his chest.
King survived after doctors discovered the blade was perched on his aorta, where a single sneeze could have proved fatal. Curry, deemed incompetent to stand trial, was committed to Matteawan State Hospital for the Criminally Insane, highlighting how mental illness intersected with the civil‑rights era.
5 Richard Dadd
Victorian artist Richard Dadd is celebrated for his intricate fairy paintings, yet few know that most of his oeuvre was produced while confined in England’s most notorious asylums—Bedlam and Broadmoor. After a grand tour that included Egypt, Dadd returned with sunstroke‑induced personality changes, eventually convincing himself he was the son of the Egyptian god Osiris.
In 1843, Dadd murdered his father during a walk, fled to France, and was apprehended after assaulting another man. Declared a “criminal lunatic,” he avoided execution and instead spent four decades creating haunting artworks behind institutional walls.
4 Laura Fair
Laura Fair’s 1870 murder trial shocked 19th‑century America, intertwining women’s rights, mental health, and even menstruation. After discovering her lover, attorney Alexander Crittenden, intended to stay with his family rather than divorce and marry her, Fair boarded a San Francisco ferry and shot him.
The defense argued temporary insanity caused by a painful menstrual cycle, but the prosecution painted her as a homewrecker, leading to a guilty verdict and a death sentence. However, suffragettes rallied to her cause, securing an appeal that overturned the first trial. The second jury found her innocent, freeing her from prison—a rare case where the insanity defense resulted in acquittal rather than institutionalization.
3 Daniel Sickles
Before his Civil‑War fame, Daniel Sickles made legal history as the first American to successfully invoke a “temporary insanity” plea after shooting his wife’s lover, Philip Barton Key II, in broad daylight near the White House. The affair between his wife Teresa and the young lawyer ignited Sickles’ fury, leading him to fire three shots on February 27, 1859.
Although Sickles confessed, his defense team argued that the shock of the betrayal drove him temporarily mad, justifying the killing to protect his wife’s honor. The jury, swayed by this narrative, returned a “not guilty” verdict, marking a landmark moment for the insanity defense in U.S. jurisprudence.
2 John Hinckley Jr.
John Hinckley Jr. captured worldwide attention on March 30, 1981, when he attempted to assassinate President Ronald Reagan. Obsessed with the film “Taxi Driver” and its star Jodie Foster, Hinckley emulated the movie’s anti‑hero, even stalking Foster before deciding to shoot the president.
During the trial, Hinckley’s lawyers presented a diagnosis of schizophrenia, while prosecutors argued his actions were premeditated. The jury ultimately found him “not guilty by reason of insanity,” leading to a 35‑year institutionalization that ended with his 2016 release. His case spurred the 1984 Insanity Defense Reform Act, tightening the standards for such pleas.
1 Daniel M’Naghten
Our final figure, Daniel M’Naghten, ignited a legal revolution in the mid‑19th century. A Scottish woodworker, he attempted to assassinate Prime Minister Robert Peel in 1843, mistakenly killing Peel’s private secretary Edward Drummond.
M’Naghten claimed paranoid delusions that the Tory Party persecuted him for his opposition vote. His police statement detailed a sweeping conspiracy that drove him to madness. The defense argued he suffered monomania—a singular, insane fixation—rendering him unable to discern right from wrong. Both sides’ medical experts concluded he was insane, leading to a verdict of “not guilty by reason of insanity.” This outcome birthed the M’Naghten Rule, still a cornerstone of insanity‑defense jurisprudence today.