One of the problems with studies that examine the effects of violent imagery is that they typically use mentally healthy psychology students. If you want to do a meaningful study, show movies like Body Double and Copycat to a group of sexual psychopaths the day before you release them.

Psychiatrists are usually very well imbued with the clinical role, where helping the sick person is the goal. And that's quite incompatible with the truthseeking role. That's probably true of the other fields, too, but maybe more so of the personalities that gravitate toward psychiatry. They tend to care about people and wish to be helpful.

Celebrity stalkers also are not necessarily fixated on one person as the public thinks. Rather, they tend to switch targets, going from, say, an athlete to an actor to a politician.

I like to have success experiences rather than failure experiences. So I'm more likely to compete in things I'm good at, and more likely to spend time on the things I expect to succeed at.

I do think a lot of sexual violence stems from experiences in childhood or at puberty. Some people become sadistic after suffering early abuse at the hands of parents, relatives or friends. But for others, the seed is planted in the formative years by the conflation of images of violence with those of sexual arousal. Magazines, TV shows and, especially, slasher movies are masters at doing this.

Killers seldom meet the legal standard for insanity, which is quite different from the way most people use the word every day. Killers may be disturbed, but that doesn't necessarily mean that they can't tell right from wrong or are compelled to maim or murder.

Only the individual can decide what level of risk she can tolerate and what level of freedom she's willing to sacrifice for the sake of safety.