The primary problem with almost all serial killers is simply ASPD, Antisocial Personality Disorder, derived sociopathy or primary psychopathy. It is present in almost 100% of such cases. Most everything else is rather secondary to this primary character disorder, which is the most prominent symptom.
Very rare is the serial killer without this disorder, although there have been a few. I remember a long-distance trucker who turned himself when he walked into a Northern California police station with a woman’s breast in his top shirt pocket. He had camped out in forests while trucking and had picked up women and killed them. He kept the body of one in the truck for three or four days and drove around with it.
Experts said he was quite unusual in that they said he actually felt bad about what he had done. I wonder how bad he really felt though. You could not get me to drive around in a truck with a dead woman in the back for very long. I would go into severe panic pretty fast, would stop the truck, get out and start walking or probably running away. I would not be able to walk around with a woman’s breast in my shirt for long either. I would completely panic almost right away, take the shirt off, throw it on the ground and start running. But then I am a pretty guilty type person with a strong conscience.
Based on that, while I am sure he may have felt some guilt for his killings, the fact that he was able to drive around in a truck with a dead woman in the back for 3-4 days shows without completely flipping out shows to me that he didn’t feel that much guilt, certainly not on the level that most of us would. And the fact that he could rather calmly walk into a police station with a cut off breast in his pocket without flying into total panic shows to me that he didn’t feel that bad about it. So guilt, even when it is present, is not as strong as in most of us, otherwise they would not have even done such horrible things in the first place.
Sexual sadism is also often present, and I have heard that Sadistic Personality Disorder is very common. Juvenile delinquency, voyeurism, exhibitionism, burglary, prowling, petty thievery, etc. typically precede the serial killings. When the serial killer starts killing, he usually has a fairly long rap sheet of more minor offenses. The murders are best seen as an escalation of a chronic criminal character type.
The ones who kill children are typically though not always preferential or fixated pedophiles. Certainly the ones who kill only children are preferential pedophiles. There is a type of pedophile called a mysoped, which is a sadistic pedophile. They are not very common. I doubt if 5% of pedophiles are like this, but these people are very dangerous. Probably almost all serial child killers are mysopeds and these crimes often have a sexual basis.
95% of rapists are the type that rarely if ever go serial, but the sadistic rapist, composed of no more than 5% of rapists, is very dangerous. Most if not all rapist serial killers are sadistic rapists.
The rage rapist is dangerous, but he generally does not intend to kill his victim although he assault her. If she fights back or gets difficult, he can fly into a rage and beat her so badly that she dies but again he usually does not intend to kill. I doubt if these types go serial much if at all. Serial killers intend to kill; rage rapists do not.
Malignant narcissism, the disorder, believe it or not, of our wonderful President, is also present sometimes. Ted Bundy was a malignant narcissist. Yes, our wonderful President has the same mental illness as Ted Bundy! Comforting thought.
A few have Schizoid Personality Disorder, and some of the more disturbed ones have Borderline Personality Disorder.
Schizotypal, Paranoid and Narcissistic Personality Disorders are rare if ever seen in serial killers. Schizotypals are probably too disorganized and decompensated and just out and out strange to commit such crimes. The serial killer must blend in, and schizotypals do not do that. A few schizotypals have committed mass murders. James Holmes the Aurora Batman Theater Shooter, was a notable case. But note that he was caught immediately.
Paranoid PD is rarely if ever seen. These people tend to be rather retiring and like to hide away from a hostile world. They also do not like to call attention to themselves from a hostile world. They are suspicious and distrustful by nature and this makes it hard for them to blend in well with ordinary society as serial killers often do.
Narcissists are usually too self-centered to kill. While narcissists are often very mean, the disorder is usually well-controlled in that the rage rarely escalates to homicide. There have been a few cases of NPD’s committing mass murder, usually of their families.
The case of Jeffrey MacDonald, the mass murdering physician of Fatal Vision, seems to be such a case. This is a superb true crime case by the way.
Also narcissists think that if they kill, they will get caught, and if they are in prison or jail they will not be able to live this wonderful life they are supposed to be killing. They are “too cool to kill.” Killing would mess up all their wonderful plans to exploit others and hold them up to contempt by millions of people, which the narcissist would have a hard time taking. The narcissist is “too good for prison.” Prison would be such a crushing blow to their self-image that it would very hard to take.
However, malignant narcissists can be very dangerous because this is a combination of psychopathy, sadism, Paranoid PD and Narcissistic PD. When you weaponize NPD with paranoia, sadism and particularly psychopathy, you create a dangerous illness.
Cluster C Personality Disorders like Passive-Aggressive Personality Disorder, Self-Defeating Personality Disorder, Dependent Personality Disorder and Obsessive Compulsive Personality Disorder are rarely if ever present in these types. These are PD’s where aggression is mostly displayed passively, and serial killers display aggression actively, not passively.
Mood disorders do not seem to be common. Bipolar Disorder is not common, and serial killers are rarely if ever depressed. They displace guilt and loathing outwards instead of pushing it inside of themselves as depressives do. Depressives are passive, and depression acts as sort of a freezing agent in that it tends to immobilize people by its nature. Men in general tend to either experience less depression than women or mask it with other things such as anger and rage, drinking, drugs, gambling, promiscuity or even workaholism. It is simply not acceptable as a man to be depressed, so depressed men simply channel their depression into other things and say they are not depressed, they are just drunks or workaholics, for instance.
Substance and alcohol abuse issues are quite common with serial killers, but the better ones are more sober, as drinkers and dopers tend to be scattered and unreliable and serial killers must be on the ball 24-7.
Only a few are psychotic. 2% of serial killers are psychotic. Psychotic people can barely organize a trip to the bathroom. How are they going to plot out elaborate and professional serial homicides?
They are motivated by many things, but your typical rape-murders of murders of attractive young women almost always have a sexual component. I would call these serial killings lust murders. The Germans coined the term. Even among the lust-murders, there are a number of different types. Some are motivated by purely sexual desires, others get off specifically on killing and the power gained from it, others are hunter types who get pleasure from the hunt and chase as if they were hunting an animal, which they are of course, but when we refer to hunters, we are always talking about hunters of non-human animals.