We can group the motivations of serial killers into three main types, which each include some pathologies ranging from a killer to another.
The motivation that can be described as “psychotic”, often comes under psychoses, and also hallucinations. The killer says he is driven to kill by higher entities, including God or the Devil. They are often prey to schizophrenia, and pulse murders so often disorganized. As it was the case of David Berkowitz or even Richard Ramirez.
The “moralistic” killer generally don’t suffer from psychosis or hallucinations, but has a very high opinion of morality, of right and wrong. They often see themselves as sporting a mission to eliminate what they consider immoral. Generally, prostitutes, homosexuals, etc. The famous Jack the Ripper is the most telling example.
The serial killer that can be considered as “hedonist”gives a notion of
intense pleasure to his murders. Violence, murder and domination of the victim is then about sexuality and possession. The hedonistic killer is often highly organized and can be pathologicaly psychopathic. The most obvious examples are Dennis Rader and Ted Bundy.