"You see, I truly believe that murderers are mentally ill," she explains. "Their brains don't work like the rest of ours do. To deliberately kill someone requires crossing a profound boundary. Most of us couldn't do it. We couldn't even think about it. But they can. They do. Why? Because they're mentally ill. And fundamentally, as a society, I believe it is barbaric to kill people who are ill."
That doesn't mean Sharp thinks murderers should be excused for their behavior or set free.
"Clearly, we need to lock these people up, and keep them away from the rest of us," she continues. "Because they're not going to stay within acceptable bounds. They're a danger to others." But she says most of us make the mistake, when we hear about a murderer, of projecting that they're like us and simply choosing to do this heinous crime. And so, imagining ourselves doing something so terrible, we feel they should be severely punished for that choice. "But," Sharp argues, "they're not like us. That's why they can do it."
Part of why more of us don't view murderers that way may be because of how we view what constitutes "mental illness," or someone who is mentally ill. The legal definition of innocent by reason of insanity requires that a person not be aware of what they were doing, or the consequences of it, at the time of the crime. Likewise, the bar for exemptions of incompetence or mental retardation require an extreme level of debilitation. But many mentally ill people are far more functional than that. Indeed, most psychologists would say that all of us sit somewhere on the spectrum of traits included in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). A person who is classified as "mentally ill" simply sits at a much more extreme point along that spectrum.
So, in many ways, or until a crisis precipitates a dysfunctional episode, a mentally ill person can appear perfectly rational and "normal." And yet, their internal world is very different. What is irrational or unreasonable to most of us can seem very reasonable to them.
"Murderers seem to have no appreciation of boundaries," Sharp explains. "And it shows up in all aspects of their lives. Most criminals I deal with are very narcissistic. They're blame-shifters, manipulative, and can't feel anyone else's pain but their own. A consistent hallmark, in fact, particularly of killers, is this extreme narcissism." Sharp points to the book People of the Lie, by the late M. Scott Peck, as a good description of a killer's personality disorder.
"These people are always the victim, it's always someone else's fault, they have no sense of other people's boundaries, and they really can't see how twisted that view is," she says. "It's a disorder."
Most of us would view someone who's constantly shifting blame to others and has an aggrandized view of themselves as annoying, at best, and perhaps reprehensible. But what Sharp, Peck and others are arguing is that, at least after a certain point on the spectrum, it's actually a mental disorder, like schizophrenia or other personality disorders. As in, not something the person can control or change on their own. What's more, as advances in neuroscience allow us sharper glimpses into the mechanics of the brain, it appears that some, if not all, of those disorders stem from biological or operational deficits in certain areas of the brain.
Dr. Jonathan H. Pincus, chair of the department of neurology at Georgetown University and the Veterans Administration Hospital, and author of the book Base Instincts: What Makes Killers Kill? told Malcolm Gladwell, for a New Yorker article in 1997, that of the criminals he'd examined, "all the violent ones were damaged."
Pincus and his long-time collaborator, psychiatrist Dorothy Lewis, from New York University, came to the conclusion that it was a lethal combination of childhood abuse, neurological disturbances and psychiatric illness that led someone to murder. Pincus and Lewis reported that an astoundingly high percentage of the murderers they'd studied were victims of physical abuse and head trauma as children. In two of their studies, in fact, they found that 100% of their subjects had suffered previous head trauma, from one cause or another.
Dr. Terry Kupers, a psychiatrist who specializes in forensic and correctional mental health issues, agrees. "In prison populations, it's known that 60-80% of prisoners have had serious physical and sexual abuse prior to their crimes and incarceration," he says. "And the prevalence of that is higher on death row than elsewhere in prisons."
Other forensic psychiatrists dispute those numbers--a 2001 New York Times article on Lewis and Pincus quoted Barbara R. Kirwin, a forensic psychologist and author who has also studied hundreds of murder defendants, as saying she'd found about 10 percent of them to have histories of childhood abuse. Kirwin said she'd seen "plenty" of people with normally competent brains who simply had a gross lack of empathy.
But to Sharp, an expert on forensic head trauma cases, the point is that "gross lack of empathy," not the details of how it evolved. "It doesn't matter whether the frontal lobe damage is psychiatric or traumatic," she argues. "The result is the same." In other words, even those "normally competent" brains reported by Kirwin are, in Sharp's view, not really normal.
Certainly the evidence, or perhaps just awareness, of how widespread mental illness is among criminals, and especially those incarcerated for violent crimes, seems to be growing. In 1999, the Bureau of Justice Statistics (BJS) estimated the percentage of inmates suffering from a significant mental condition at 16 percent. In a comparable report issued in 2006, the BJS revised that number upward to over 50 percent.
Dr. Kupers, who published a 2008 report on mental health issues among inmates at the Los Angeles County Jail, attributed part of that increase to the de-institutionalization of psychiatric patients who, before the 1980s, would have been committed to psychiatric hospitals. He notes that in 1955, there were 550,000 people in psychiatric units in the U.S. Today, there are less than 60,000 in psychiatric hospitals, but more than a million people reportedly suffering from mental illness in various levels of county, state, and federal jails and prisons. In a 2008 random study of Iowa state prisoners, Kuper noted, researchers found that more than 90 percent met the criteria for current or lifetime psychiatric disorders.Kuper also says that "the prevalence of serious mental illness on death row would be substantially higher than in prisons in general.