The Anatomy of Violence

by Adrian Raine

  Kevin Drum, a political blogger and columnist argues that these findings have been completely ignored by criminologists. He contacted criminology experts and none of them showed a scrap of interest.79 Why? Likely because to recognize that secular trends and both rises and falls in violence can be partly attributed to brain dysfunction—and not to better policing or to gun control or to the end of the crack epidemic —would be to recognize the explanatory power of biology theories. Currently that’s something very difficult for many social scientists to accept.

  Cruel Cadmium

  At a McDonald’s next to the post office in the community of San Ysidro, near San Diego, at 3:40 p.m., on July 18, 1984, a middle-aged man walked in with a 9-millimeter semiautomatic Uzi and unloaded 257 rounds of ammunition into the customers. The shooter, James Oliver Huberty, killed twenty-one people and wounded nineteen others.80 His victims ran the gamut in age from just seven months to seventy-four years.

  What on earth made Huberty do it? Cadmium is a very likely culprit. An analysis was made of Hubert’s hair after he was shot dead by a SWAT team sniper perched on the roof of the next-door post office. The results were nothing short of astonishing. In the words of William Walsh, the chemical engineer conducting the analysis, “He had the highest cadmium level we have ever seen in a human being.”81 Huberty’s lead levels were also high, so he had a double hit. There’s no mystery as to why he had multiple metals in his body. Huberty had been a welder for Union Metal for a number of years until he gave it up. The reason he left his welding position? In an exit interview that he gave to his employer upon leaving, he said, “The fumes are making me crazy.”82

  So cadmium can be a killer, not just in people like Huberty, and not just in the United States. Certainly, hair samples from violent offenders in the U.S. show them to have more cadmium than nonviolent offenders.83, 84, 85, 86 High hair-cadmium levels also characterize U.S. elementary schoolchildren with behavioral problems.87 The same is true for schoolchildren in China, a leading producer of cadmium. The Dabaoshan mine in the city of Shaoguan in the Guangdong province is a multi-metal mine. Water is used to leach the ore, and the waste water is then transported by rivers to local villages, delivering a large dose of heavy metal to the villagers. The result is that the crop region in this countryside has sixteen times the recommended level of cadmium. A study of schoolchildren living downstream from the mine showed that hair-cadmium levels explain 13 percent of the variation in their aggressive and delinquent behavior.88 Cadmium is quite a heavy-metal key on the biological key chain unlocking the etiology of violence.

  It’s not hard to see how people living near a mine are exposed to cadmium, but what about the rest of us? Not surprisingly, cadmium is a hazardous substance that can cause death and is banned by the European Union for use in electrical equipment. Yet about 75 percent of all cadmium in the United States is used in rechargeable nickel-cadmium batteries rolling around your home right now. Not too harmful there, perhaps, but cadmium does find its way into the environment from municipal waste grounds and fossil fuels because products containing cadmium are rarely recycled.

  The people most susceptible to cadmium? Smokers. They inhale about 10 percent of the cadmium content of a cigarette, which gets nicely absorbed into the bloodstream from the lungs.89 They end up with five times the cadmium levels of nonsmokers.90 The rest of us get exposed too, because foods like offal (the internal organs of animals) and cereals91 account for 98 percent of our cadmium intake. In contrast, seafood, which we saw earlier to be associated with lower violence, accounts for only 1 percent.92

  The twist here is that the amount of cadmium acting on your body is a function of other factors. Iron blocks the intestinal absorption of cadmium.93 Women on vegetarian diets have reduced iron levels and they also have increased cadmium exposure. If they smoke as well they will have an exponential increase in cadmium. This may partly explain why low iron is associated with violence—individuals with low iron levels are more susceptible to the negative effects of cadmium on the brain.

  Mad Manganese

  Everett “Red” Hodges is one of those larger-than-life characters whose charismatic and witty stories blend with forceful argumentation to make you believe almost everything he has to say. His sons have been both perpetrators and victims of crime. One was a rebel without a cause who got into a load of trouble as a juvenile delinquent. The other was mugged in a parking lot and very badly beaten up, suffering brain damage as a result. “My son was damn-near murdered,” Red said in an interview. “I know the anguish and suffering that families go through. And you can’t put a price on it.”94

  Red reasoned that if the criminal justice system had done a better job of dealing with the neurobiology of violence, his son and many others would never have been the victim of violence. The anguish of many family members would have been spared.

  Red pins the blame on one particular metal—manganese. Having made a good deal of money in a Bakersfield oil field in California, Red Hodges sank a million dollars into funding efforts to investigate his hypothesis. Working with Red, Louis Gottschalk at the University of California, Irvine, demonstrated that three different samples of violent criminals had higher levels of manganese in their hair than controls did.95 Roger Masters at Dartmouth University similarly showed that areas in the United States with higher levels of manganese in the air have higher violent-crime rates—even after controlling for multiple socioeconomic confounds.96

  At the same time, the manganese debate is a political hot potato, and it’s hard to know who’s right and who’s wrong. Critics reasonably argue that the evidence is mixed and that we cannot easily untangle cause-and-effect relationships from correlational studies.97 What helps here are longitudinal studies involving teeth. The cusp tip of the first molar gives a handle on manganese exposure halfway through pregnancy—a time when a fetus’s brain is rapidly expanding. Using these teeth, researchers showed that kids with high prenatal manganese levels had disinhibited, antisocial behavior across the board on a host of antisocial-behavior measures.98

  What causes excessive manganese exposure during pregnancy? A deficiency in iron—the micronutrient that when low is associated with high antisocial behavior—enhances manganese absorption. Women with low iron levels absorb about four times more manganese than women with high iron levels.99 An early postnatal source of manganese is soy infant formula, which has eighty times the amount of manganese that natural breast milk has. It’s possible that the higher IQs found in breast-fed babies may be due to formula-fed babies’ being exposed to high manganese, because manganese excretion is controlled by the liver. The livers of babies are underdeveloped, and consequently they are less able to excrete manganese. The excessive manganese could then result in poorer brain functioning and lower IQs.

  Put the two together and you begin to build a recipe for violence. Pregnant mothers have a tendency to have low iron. This will result in increased manganese exposure to the fetuses. Then, when the nippers are born, they get soy milk with a hefty dose of manganese that their little livers cannot deal with. The potential result? One more strike on the brain. Higher manganese levels in children can result in impairments in cognitive speed, short-term memory, and manual dexterity.100 As we noted earlier, this neurocognitive dysfunction predisposes individuals to violence. Furthermore, manganese reduces serotonin, a neurotransmitter that when low causes a predisposition to impulsive violence.

  Given this, perhaps it’s not too surprising that fifteen studies on workers exposed to manganese in all corners of the world—including Chile, Great Britain, Egypt, Poland, Brazil, the United States, Scotland, and Canada—without exception report significant mood disruption, including aggression, hostility, irritability, and emotional disturbances.101 In Chile the term used is locura manganica—meaning “manganese madness.” It refers to violence, mood disturbances, and irrational behavior. It’s just the type of craziness that James Huberty reported as the reason for leaving his welding job, this time for another ma
d metal—cadmium.

  It has been documented that the aggressive acts of workers exposed to manganese result in “stupid” crimes that are not premeditated and motivated by gain, but more a result of brain impairment resulting in poor emotion regulation and impulsivity.102 Not surprisingly, low intelligence is an extremely well-replicated risk factor for violent offending, a risk factor that could in part be caused by an excess in manganese.

  Mysterious Mercury

  Moving from manganese to mercury you might expect the same pattern of results to emerge. But they don’t. Mercury is mysterious. Of all the heavy metals, this one may or may not play a role in violence—a fact that is both striking and enlightening. Mercury is toxic to the brain and other body organs, with about half of human-generated mercury coming from coal plants. Dental amalgams are another source, and fish are also argued to be a major dietary contributor.

  Despite its toxicity, to my knowledge there are no convincing demonstrations that antisocial and violent individuals have higher mercury levels. It is also surprising that there are so few studies on mercury levels and cognitive ability in community populations. Two major prospective studies that have been done on blood-mercury levels and cognitive-behavioral functioning show conflicting findings.103 One study, conducted in the Faroe Islands, between Scotland and Iceland, found high mercury to be associated with poorer cognitive functioning.104 The other study, in the Seychelles, which is just up the road from Mauritius, in the Indian Ocean, found no association between mercury and cognitive-behavioral outcomes.105 Reviewers are at a loss to explain the discrepancy, putting the difference down to “culture.”106

  Yet if we put together a few seemingly unrelated facts, these geographically contradictory findings can make sense. Where do people get mercury from? Supposedly from eating fish that are high up in the food chain—particularly shark, swordfish, and king mackerel, which are certainly on the no-go list for pregnant mothers. In the Faroe Islands they also eat a whole load of pilot whale, especially outside the capital city. What’s the deal with pilot-whale meat? It’s not just very high up in the food chain and high in mercury, but it’s also low on selenium.

  Selenium? This is a mineral that defends the brain against “oxidative stress,” a process in which the brain cell takes up too much oxygen, resulting in the production of free radicals that damage DNA and the cell membrane, resulting in cell death. Selenium not only protects against this damage but, more important, it binds with mercury. Like a magnet, selenium latches onto mercury and keeps it from binding with brain tissue, thus preventing brain and cognitive impairment.

  If you think about it, fish seem to do okay with all that mercury leaching out of the seabed, and many species are packed with selenium. Going back to the two studies with contrasting results, the high-mercury and low-selenium diet in the Faroe Islands translates into poor cognitive and behavioral functioning. And yet in the Seychelles, pregnant women are also exposed to mercury, eating twelve portions of fish a week. That’s a lot, twelve times the consumption of American women. So what is different in the Seychelles and the Faroe Islands? In the Seychelles they do not eat pilot whale, which is low in selenium. Instead they eat fish high in selenium that buffers them from mercury and its cognitive impairments. Their diet thus protects them against any damaging effects of mercury, as well as providing a high dose of the beneficial omega-3. We shall return to omega-3 in a later chapter when we pose prevention strategies to fight violence.

  MENTAL ILLNESS MAKES FOR MEANNESS

  So we are seeing that biology plays out in the environment and in the physical-health arena when it comes to the makings of malevolence. Some heavy metals take their toll on the brain and predispose people to violence. But health is a multifaceted construct, and it acts in ways other than diet and environmental toxins to shape violence. Let’s not forget mental health. Biological impairments can also make men mad, and madness can make men mean. Women too, perhaps even more than men. Mental illness has its roots in genes and neurotransmitter abnormalities that mess with our minds. And it’s when our minds are mucked up that we are most prone to violence. One prominent and major mental illness that can do this is schizophrenia.

  I’ve long had an interest in schizophrenia because it was, in a way, pivotal in moving me out of accountancy and into criminology. Not that I became psychotic adding up all those numbers at British Airways—although at times I did think I was losing my mind somewhere within those cabin-crew accounts. But this clinical disorder did radically change my life. Haven’t we all had those pivotal moments in life when a seemingly chance, inconsequential event changed everything? You pick up some random book, just like you picked up this one, and something clicks. The next thing you know, your life takes a sudden turn—all because of one capricious, unpredictable, and seemingly innocuous experience.

  In my case it was a Saturday morning just before lunch in the early summer of 1973, and I was bored to tears working at Heathrow. I knew I’d made a really bad life decision in becoming an accountant, and I was absolutely miserable—had been for months. How had I messed up so badly? I was hungrily hunting for some books at a bookstore in Hounslow where I lived to read over my Saturday lunch treat—an “American” cinnamon apple pie and ice cream—and it leaped out at me. A slim paperback by R. D. Laing and Aaron Esterson entitled Sanity, Madness, and the Family.107 Laing’s riveting collection of eleven case studies of schizophrenic patients challenged the prevailing medical model that schizophrenia was a brain-based disorder. Instead this existential psychiatrist argued that schizophrenia had an environmental basis stemming from faulty communication within the family. Schizophrenics have outrageous and bizarre beliefs, but their madness becomes understandable when we consider the context of the family.

  I had an epiphany. It was all making sense. So that’s how I ended up as such an oddball—it was all my nutty parents! It was a revelation that made me determined to understand myself more and to study psychiatry (I ended up studying psychology instead), to challenge the biological model of mental disorder (I eventually did the opposite), and to work in hospitals helping schizophrenic patients (trade that for four years in prison helping psychopaths). Books change our mind-set and sometimes our life—though not always in the way we anticipate, and not necessarily in the right way.

  Laing and Esterson weren’t exactly right either. Schizophrenia turns out not to be caused by faulty parent-child communication patterns but is instead a debilitating, brain-based, neurodevelopmental disorder characterized by delusions, hallucinations, thought disorder, lack of emotion, and disorganized behavior. Affecting about 1 percent of the population around the world, it frequently hits women in their early twenties and men in late adolescence, with about 40 percent of male schizophrenia cases occurring before the age of nineteen—an intriguing fact given that these late adolescent years are also the peak age for violence in men.108

  What’s also intriguing is that when we look at the biological factors that are related to schizophrenia, we find many of the same risk factors that we have seen earlier characterizing violence. Things like frontal-lobe dysfunction, neurocognitive impairment, fetal maldevelopment, birth complications, blunted brain responses to stimuli we should normally pay attention to, and orienting abnormalities. To be sure, crime and schizophrenia are certainly not the same condition. They present very differently to the clinician. And there are risk factors like low resting heart rate that are unique to crime and unrelated to schizophrenia.109 Yet, at some causal level, there is a degree of common ground.

  That common ground expresses itself most strongly when we look at the link between violence and schizophrenia. Large-scale epidemiological studies from many countries around the world now attest to the fact that schizophrenia patients are much more likely than normal controls to have a history of violent and criminal behavior. Turning the issue around, delinquent and criminal populations are more likely to show higher rates of psychotic disorders than the general population. This relationship between
violence and schizophrenia is not weak. If you are a schizophrenic male, you are three times more likely to kill than someone of the same social background and marital status who is not schizophrenic. If you are a female schizophrenic, you are twenty-two times more likely to kill than a nonschizophrenic female.110

  These are striking statistics, and we should be cautious in interpreting them. Many psychiatrists and families of schizophrenic patients do not want to hear this message.111 It’s hard enough for someone with schizophrenia to have to carry the burden of this debilitating illness, let alone to be labeled as violence-prone. It’s true that most schizophrenics are not dangerous and neither kill nor perpetrate violence.112 But the harsh reality is that the neurodevelopmental ravages perpetrated on the brains of schizophrenic patients during childhood and adolescence make them less able to regulate their emotions and hold back their anger as adults.113

  You might accept that schizophrenia is a neurobiologically based mental disorder. You may even agree that schizophrenics are more likely than others to kill. But you could counter that schizophrenia is a rare mental illness, so surely it cannot account for much violence. And you’d have a point. What we next need to consider, therefore, is that there is a “watered-down” version of schizophrenia with a higher base rate in the general population.

  We have exactly that in a clinical condition called schizotypal personality disorder.114 Instead of hearing voices of nonexistent people, as schizophrenics do, schizotypals mistake an actual noise in the environment for someone speaking. It’s not entirely uncommon. I was in my hotel room at a conference in Tuscany washing and shaving in the bathroom sink when I heard a woman very close by, shrilly saying, “Well, hello.” Startled, I looked around. I looked in the bedroom. Nobody. How peculiar. I went back to washing, and heard the same thing again. It had to be outside in the corridor. I opened the door to my bedroom, but no one was standing out there. This was seeming more bizarre. Going back to washing and turning on the faucet, I realized that the squeaky female voice was none other than the squeaky tap. About every month or so I hear someone calling my name in the street, and look around to find myself mistaken again. Technically, the symptom is called “unusual perceptual experiences”—you mistake sounds for voices and shadows for objects and people. But I’m all right, I tell myself.