NEW YORK (Reuters) - Unless James Holmes chooses to say why he went on the lethal shooting spree he is accused of in a Colorado movie theater last Friday, the analyses offered by forensic psychiatrists, based on their study of other mass murders, may be as close as we get.
From what is known of the attack and his life so far, experts say Holmes was probably not suffering from as serious a mental illness as Jared Loughner, who was diagnosed with paranoid schizophrenia after killing six people in Tucson, Arizona, in 2011.
"People want to believe that someone who does something like this must be floridly psychotic," said Louis Schlesinger, professor of forensic psychology at the John Jay College of Criminal Justice in New York, who has studied mass killers since the 1970s. "They think, ‘ah, he's mentally ill; now I understand.' It makes people feel they and people they know would never behave this way."
The scarier prospect is that Holmes's psychological illness was more common, less severe, and not easily detectable.
As experts in forensic psychiatry try to figure out from afar what is wrong with Holmes, they are focusing on three details of the shooting: The targets were strangers to the killer, not colleagues or acquaintances; the shooter did not commit suicide or invite his own death at the hands of police; and Holmes warned authorities about his booby-trapped apartment before the explosives he rigged killed anyone.
Murdering 12 strangers and shooting dozens more points to a generalized paranoia and rage against the world rather than a specific grudge, forensic psychiatrists say.
"Most mass murderers kill specific people for specific reasons," said criminologist James Alan Fox of Northeastern University, who with colleague Jack Levin has studied every mass murder in the United States since the early 1980s. "They kill the bosses who fired them, the professors who wronged them. These are revenge killings."
One of the many mass murderers who fit this profile is Nathan Dunlap, who killed four employees at a Chuck E. Cheese restaurant in Aurora in December 1993, after he was fired and reportedly felt his boss had "made a fool" of him.
Holmes was in the process of withdrawing from the University of Colorado's graduate program in neuroscience, which has prompted speculation that academic failure might have played into his motives. But he did not target either professors or fellow students.
That suggests his resentment was directed elsewhere than academia. It may put him closer to the second most common kind of mass murderer: one who targets people who represent what they consider the source of their woes, experts said.
"These killers don't know the victims personally, but they're getting back at a certain kind of individual," said Fox.
Marc Lepine, for instance, separated men from women in a classroom at the Ecole Polytechnique in Montreal in December 1989 and shot nine women, six fatally. He killed eight more women as he rampaged through the corridors and cafeteria, claiming feminism had ruined his life.
Seung-Hui Cho killed 32 students and teachers at Virginia Tech in April 2007, the deadliest murder by a single gunman in U.S. history. Cho called other students "hedonistic" and "brats" who had "raped" his soul and had "everything" they wanted, such as "Mercedes … , golden necklaces … , trust fund … , vodka and cognac."
If the victims did not represent a category of people Holmes specifically hated or resented, then he would fall into the category of mass murderers who target strangers indiscriminately, the least common profile.
In such cases, "the perpetrator has a grudge against the world and feels that if it were not for the system, things would have gone better for him," said Fox. "He doesn't care who he kills as long as he kills a lot of people."
About 16 percent of mass killings target complete strangers, said Levin, professor of sociology and criminology at Northeastern. They are not necessarily more or less severely mentally ill than murderers who target acquaintances or people who belong to a group they resent, but their pathology takes a distinct form.
Wide-ranging suspicion that the world has treated you unfairly can be a sign of paranoid personality disorder. The American Psychiatric Association defines that condition as "a pervasive distrust and suspiciousness of others such that their motives are interpreted as malevolent, beginning by early adulthood."
The condition has an estimated lifetime prevalence in the United States of 4.4 percent; schizophrenia affects 1.1 percent of U.S. adults, according to the National Institutes of Health.
There is no evidence Holmes felt paranoia, nor have any records emerged showing he was ever diagnosed with or treated for any form of mental illness. But the absence of such evidence does not rule out the disorder, experts said.
"Of all the psychoses, paranoia is the most difficult to detect," said John Jay's Schlesinger. "Unless you broach a particular subject - like work, if someone thinks his boss is out to get him - they might very well seem normal if you sat down and talked to them. In Holmes' case, it could have been an encapsulated paranoia, focused on one particular area of life where he thinks people are out to get him."
If so, Holmes would fit the profile of the mass murderer whose act has been triggered by a severe strain and led him to externalize blame, Levin and Fox's studies have shown.
"They blame everyone but themselves for their frustration and disappointment," said Levin. "Then there is some acute strain, which usually takes the form of a catastrophic loss - of a job, of money, of a child in a custody battle, or of academic standing. ... The catastrophic strain sets the stage for the planning phase of the mass murder."
Another clue to Holmes's mental state is that he clearly intended to survive the massacre, wearing body armor during the attack and then surrendering to authorities.
In contrast, say experts, most of the mass killers they call "pseudocommandos" - those who kill in public, plan meticulously, and are armed to the teeth - expect to die in their rampage, noted Dr James Knoll, a forensic psychiatrist at SUNY Upstate Medical University in Syracuse, in a 2010 study. Virginia Tech's Cho killed himself, as did the two teenagers who fatally shot 13 people at Colorado's Columbine High School in April 1999.
"That (Holmes) didn't is an indication that he was different in psychological terms than the others we've studied," said Levin.
Holmes's warning to authorities that he had booby-trapped his apartment before the explosives could kill anyone suggests "he felt he had accomplished his mission," said Fox. "He showed the world how fearsome and powerful he was."
President Barack Obama did not say the name of the suspected killer in his remarks in Aurora last Sunday. Some reporters, notably CNN's Anderson Cooper, have suggested the press not use Holmes's name, denying him the infamy he may have sought.
Whether mass killers are motivated by a desire for notoriety "is hard to generalize," said Schlesinger. "Some are, some aren't. All we can say is that infamy is a motivation for some."
Were there warning signs that, if acted on, might have prevented the tragedy in Aurora?
Based on the scores of mass murderers he has studied, Northeastern's Fox says there is "a consistent profile in which someone has a history of frustration and failure despite promise and aptitude. But they also have a very weak support system: They don't have close friends or family nearby to turn to for help or to put their thoughts in perspective."
Holmes has been described by fellow students as quiet and reserved, though not an outright loner. Fox warns that not even more dramatic social isolation is a reliable warning sign.
"There are thousands and thousands of people who fit that pattern and do not kill anyone," Fox said. "You can't use it to predict who will become (a mass murderer). These are not red flags, but yellow ones. They become red only in retrospect, when the blood flows."
Editing by Michele Gershberg and Prudence Crowther