An angry but immature and insufficiently armed 15-year-old went on a rampage at a Louisiana middle school, a crime that officials say was planned far in advance, as evidenced by journals kept by the gunman. With the exception of the all too real body count and injuries, this almost felt like a childish playacting of a massacre. It fit the mold of the mass murder, through the angry journal entries to the shooter's attempt on his own life, which left him in "critical but stable condition" but alive.
He "geared up" in camoflauge, dressing up for the part, and told a teacher to "Hail Marilyn Manson," an odd and very immature statement. But someone who thinks they can solve their problems in a hail of bullets is hardly a role model of humanity. His journal reveals phrases like "y'all will die."
This shooter was 15, with a still developing and still immature mental capacity, and, most likely, ruled by hormones rather than logic. Regardless of age, once a man (usually) has come to the decision to run rampant with a firearm as retribution for perceived injustices, he has ceased to be a rational human being and is ruled by overactive emotions, like any teenager.
The serial killer, in emotional processes, is also, in a way, a perpetual adolescent, demanding that what he needs is more important than anything else in the world, even if what he "needs" is to commit murder. The vast majority of teenagers are not violent, although their demands for possessions and an independence for which they are not ready can border on insistent and almost violently pushy. Killers, like addicts and teenagers, need instant gratification, and are easily bored and need higher levels of stimuli to keep them interested. Ted Bundy's college girlfriend dumped him (this was the trigger on his festering hatred of women) because, among other factors, she thought he was "immature." Gainesville Ripper Danny Rolling was also called immature by a police psychiatrist. Ed Gein had a childlike inability to cope with the outside world after the death of his domineering mother, which lowered him into insanity. Somewhere along the way, the emotional development of these men stalled, while they physically grew into adult men and, in most cases, developed higher mental capacities that allowed them to trick their victims and outsmart law enforcement. Physical and mental strength, combined with an adolescent selfishness and demand for instant gratification, took men damaged by biology or abuse down a murderous path.
Adolescence is also, particularly for men, a hypersexual period, which doesn't taper off until the early to mid 20s (or, an argument can be made, for the rest of their lives). Older men, with some exceptions, don't often begin serial murder careers (angry men of this age are more likely to go on shooting rampages) because, possibly, even if the crimes themselves have no sexual element, most serial killers gain a sexual satisfaction from murder. In the first episode of the second season of Dexter, after commiting his first murder in several weeks, as Dexter plunges the knife into his victim, his face looks like one in the midst of an orgasm. That many serial killers choose the phallic knife is potentially significant to the Freudians among us, and, while Jack the Ripper's victims were not sexually assaulted, profilers theorize that the stabbing was the Ripper's substitute for sex. Male serial killers usually begin their careers in their late teens or early 20s, where they are legally adults but still hypersexual adolescents. Female serial murderers, on the other hand, if they are not acting as accomplices to male killers, tend to begin their killing later in life, as Aileen Wuornos did in her 30s; women reaching their sexual peak in mid-adulthood rather than adolescence.