Serial Killers: Insane or Super Intelligent?

Perhaps film and television have brought on the misconception that serial killers are either/or. Either a serial killer is insane or has superintelligence. That is not factual.

Taking the first misconception, insanity, serial killers are rarely diagnosed as insane, but a common diagnosis among serial killers is an antisocial personality disorder. In an argument, some debate this issue with, “How can a human repetitively kill other humans and not be insane?” While on the surface, that would seem logical, nonetheless, that is not true. The current requirement for a diagnosis of insanity is that the offender did not understand that the murder is wrong in the legal sense when the murder occurred. Because of this requirement, serial killers very seldom meet the criteria.

Jeffrey Dahmer, for instance, arguably one of the world's most heinous serial killers, knew his murders were illegal and, by his own admission, tried to stop murdering. On one occasion, Jeffrey moved in with his grandmother, started attending church, and tried to end his killing. On the contrary, as he stated in his confession, the urge to kill took over, and he began his murderous lifestyle once again. His murders and cannibalism did not make him insane, as he knew his actions were illegal at the time he was committing them. Most other serial killers follow the same mold.

The second common belief is that, if not insane, then serial killers possess superintelligence. That, too, is not true. In fact, serial killers follow the societal norm regarding intelligence. There are those on the far ends of the bell curve, but most fall in the relatively same pattern as the rest of the population.

There is, however, a variation among serial killers themselves when considering a classification of organized versus disorganized. Organized serial killers have a slightly higher average IQ than do their disorganized counterparts, with a 99.2 average.¹ Disorganized serial killers have a 92.8 average, with the average IQ among all serial killers having a 94.7 average.¹ The far ends of the bell curve show extremes of 54 on the low end and 186 on the high end.¹

Yes, some serial killers are insane, and some do possess superintelligence, but for the most part, a serial killer being diagnosed as insane or possessing superintelligence is rare.