Serial killers are amongst the most chilling and hard to understand individuals on the planet. They don't kill just once in a fit of passion or rage, but over and over again. Sometimes the victims are tortured. Oftentimes they are raped. Some serial killers even perform sexual acts on the corpses of their victims. Still others engage in cannibalism.
This is clearly abnormal behaviour, the work of a deranged and troubled mind. It is so far removed from what most people seem capable of in even their darkest moments, that most people's initial gut reaction is that the perpetrators of these ghastly crimes must surely be mad. But are serial killers necessarily insane?
First of all, we need to define the concept of insanity. From a legal perspective, a person is only judged to be insane if they cannot distinguish right from wrong. Therefore, if a serial killer knows that what he/she is doing is wrong, then he/she is not legally insane. Even if he is a schizophrenic like Richard Trenton Chase (who believed that he had to kill in order to prevent his blood from being turned to powder) this same rule applies: if he knew that he was doing wrong, then he cannot be found legally insane (Richard Trenton Chase was, for example, found sane, despite having a long history of mental illness).
But even if we adopt a broader definition of insanity - one that includes people suffering from serious mental illnesses like schizophrenia - then some serial killers still do not seem to fit. Take Ted Bundy, for example. America's most notorious serial killer was an intelligent, charming law student who's crimes showed a high level of organization. He would lure his victims to a secluded location by faking injury or impersonating a figure of authority. He disposed of the bodies and took great care so as to not leave any incriminating forensic evidence behind. He even succeeded in escaping from police custody, not once but twice. He appeared to be just an ordinary man (albeit an unusually good-looking and charismatic one). He just didn't seem to fit any standard definition of insanity.
And Ted Bundy wasn't the only apparently rational serial killer. Jeffrey Dahmer, John Wayne Gacy, and Dennis Rader (the BTK killer) would also fit the profile of the seemingly sane serial killer.
So, clearly, the answer to the question 'Are all serial killers insane?' would appear to be a resounding 'no'. It might be argued that they are all somewhat unbalanced - or just plain evil - but they are not necessarily any crazier than the rest of us. And that just makes them all the more chilling.
You might also be interested in:
Definition of a Serial Killer, Ted Bundy - The Charismatic Killer, Richard Trenton Chase - The Vampire of Sacramento