The notion that behaviours that make no sense must come from psychosis may originate from a few different mistaken assumptions.
One is confusion about the word psychosis and what exactly that means. Psychosis is a cluster of psychiatric symptoms including delusions, hallucinations, and/or highly disorganized thinking. Psychosis impairs the ability to distinguish between what is real and what is not. It can occur in the context of a number of different psychiatric illnesses, and may also be drug-induced. Regardless of the cause, the definition of psychotic symptoms remains the same.
Another mistaken assumption is that people would not be able to commit heinous acts if they were in touch with reality, so therefore they must be psychotic and disconnected from reality. However, human beings have been doing very bad things to each other for a very, very long time. Even if mental illness did make people perpetrate violent acts (which is rare), it seems wildly unlikely that psychosis spread like wildfire through, say, the SS guards in Nazi concentration camps.
So, if killing in cold blood while fully aware of one’s actions is something that can happen, what on earth is going wrong in the minds of people who perpetrate some of the most atrocious crimes, like serial killers?
One possible answer is psychopathy. It’s not a disorder in the DSM-5; the closest equivalent would be antisocial personality disorder, but taken to a more extreme level. Psychopaths lack empathy and tend to be extremely skillful at manipulating the people and situations around them to serve their own needs. They have a strong need for control and a lack of remorse for the negative effects of their actions on others. While the words themselves sound similar, being psychotic and psychopathic are two extremely different things. Psychopaths are very much in contact with reality and are in control of their actions.
The causes of psychopathy are complex and poorly understood, but this isn’t something that develops spontaneously later in life. Psychopathic individuals begin to demonstrate problems in childhood. Childhood bullying and abuse by family members are common in this population. They tend to demonstrate elements of what’s known as the Macdonald triad for predicting future violence risk: arson, cruelty to animals, and bed-wetting beyond age 12.
Characteristics of serial killers
Serial killers often have intense fantasy lives. We all fantasize to some extent, but we’re able to maintain a clear distinction between our inner world and the world around us. As children, serial killers tend not to have learned to establish these boundaries, so violent fantasies spill over into real-world behaviour.
Many of the prominent serial killers people are aware of, like Ted Bundy and John Wayne Gacy, were very deliberate and methodical, which required them to know exactly what they were doing. They are considered “organized” serial killers. They are very much in control, and none of this is consistent with a psychotic thought process.
“Disorganized” serial killers, on the other hand, tend to be more impulsive and erratic, and they don’t usually try to hide the bodies. Mental illness may be part of the picture with this subtype.
Cult leaders responsible for mass suicides or other violence (e.g. Jim Jones, David Koresh, Charles Manson) are another type of perpetrator that may fall under the idea of makes no sense, therefore must be psychotic. However, consider the level of finely tuned manipulation that would be required to exert total control over a group of followers.
Someone who was psychotic would never be on the ball enough to wage that kind of psychological campaign even if they wanted to. While the type of individuals that would engage in this type of manipulation are deeply disturbed, that does not make them psychotic.
For all the books and tv shows that try to get inside the heads of these criminals, the reality is we’re never going to get a clear picture. There is no clear “why”. What is clear, though, is we should not be assuming that serious mental illness is responsible for people doing the unimaginable.
Source: Wikipedia: Serial killers
My book Making Sense of Psychiatric Diagnosis breaks down the different categories of DSM-5 diagnoses, explaining the diagnostic criteria and providing first-hand stories of the various illnesses. It’s available on the MH@H Store, as well as Amazon and other major retailers.