Neurodevelopmental Aspects of Violence and Agression

By Emily Beard Johnson, BA, CD, Asst. Assoc. of ECE, Neurological Reorganization Practitioner

Permission to copy this article with appropriate attribution is granted. (503) 981-0635. Many of the clients seen at Northwest Neurodevelopmental Training Center inflict violence either on themselves or on others. Violence costs society a huge amount of money, as well the obvious emotional toll. According to a June 2007 study, “violence costs the United States $70 billion annually, a figure that rivals federal education spending and the damage caused by hurricane Katrina.”[1] According to the lead author of this study, this astronomical amount is, at best, incomplete, as it does not include the lingering effects of violence, such as post-traumatic stress disorder, depression, anxiety, and substance abuse. Additionally, the cost of domestic violence and self-inflicted violence (such as suicide attempts) is vastly under-reported. “There is a huge quality of life component that this research doesn’t capture. Thinking about the Virginia Tech victims, no one can put a value on the impact the violence had on those families and students.”[2] Whether we look at the actual act of violence or the lingering effects of violence, central nervous system dysfunction plays a critical role. Individuals who did not complete the developmental sequence are at heightened risk of perpetrating violence, while individuals who experience even minimal trauma are at heightened risk for the issues that can lead to violence. Neurological reorganization addresses this central nervous system dysfunction to minimize the perpetration of violence.

Altered central nervous system function is observed in those prone to violence, as confirmed by numerous studies. A March 2007 study found that “stress prevent[s] the cells, located in the hippocampus, from surviving, leaving fewer new neurons for processing feelings and emotions.”[3] Another March 2007 study found decreased hippocampus function in children exposed to stressful situations, leading to emotional and behavioral issues such as intrusive thoughts, nightmares, avoidance, and emotional numbing.[4] An additional study detected brain activity changes in abused children. As stated by the lead author, “Why does something that happens to someone when they’re two, three, or four years old have such pervasive developmental effects? This study is one way to find some of the underlying developmental changes caused by traumatic events,”[5] specifically in terms of altered neural processing of emotion. Individuals who have post-traumatic stress disorder have “show[n] altered pain processing in brain areas associated with mood and cognitive pain processing.”[6] Altered pain processing is associated with decreased compassion and empathy and increased violence. A June 2007 study demonstrated the correlation between altered brain chemistry and aggressive personality, resulting in such behaviors as “taking advantage of others, causing them discomfort, having a short temper, vindictiveness, and enjoying violent movies.”[7] A May 2007 study also drew the correlation between altered brain chemistry and aggression.[8] The central nervous system dysfunction that sets the stage for aggression and violence culminates in a June 2006 finding that up to 16 million American adults have intermittent explosive disorder, characterized by episodes of impulsive aggression grossly out-of-proportion to any precipitating psychosocial stressor.[9] This disorder also predisposes individuals toward depression, anxiety, substance abuse, financial difficulties, and failed interpersonal relationships, further perpetuating the cycle of violence.

A June 2007 study identified several behaviors that are common precursors to violence. These include lack of eye contact, inappropriate vocal tonality and volume, high anxiety, and incoherent speech. Furthermore, when complicated by mental illness or head injury, the propensity for violence escalates.[10] At a functional neurological exam, we see these and other neurological soft signs indicative of disrupted development and gauges of potential violence, including pons-level dysfunction characterized by poor pain processing and extreme forms of self-stimulation, poor facial recognition, risk taking, poor bonding through lack of eye contact, and high anxiety. We also observe impaired corpus callosum function leading to impulsivity and impaired midbrain-level stress response. A September 2006 meta-study found that individuals with personality traits such as aggressiveness, irritability, anger, Type A personality, dissipation-rumination, feelings of inadequacy or vulnerability, narcissism, self-destruction, and impulsivity display “the tendency to either engage in aggressive behavior willingly or to engage in aggressive behavior when provoked.”[11] While an individual who displays some of these characteristics may or may not be currently aggressive or violent, he or she is at heightened risk for it in the future.

The disrupted development that can later result in violence begins in utero. According to a March 2007 study, “a considerable body of evidence has emerged showing that circumstances during the fetal period may have lifelong programming effects,”[12] including cortisol regulation. Cortisol has been linked to many neuropsychiatric disorders that place an individual at heightened risk for violence. Additionally, the behavioral effects of disrupted early development are so great that, according to a December 2006 study, “99% of [three to six year olds] who do not suffer from any kind of disruptive behavior do not develop these disorders later in life. By contrast, those who do suffer from disruptive behavior continue to have the same problem five years later or develop some other kind of disorder.”[13] For children unfortunate enough to experience both disrupted in utero development and childhood abuse, the likelihood of lifelong behavioral struggles, such as social dysfunction and delinquency, skyrockets.[14] Frequently, NNTC clients fall into this category since they experience less-than-optimal prenatal care and are exposed to trauma or abuse within the first years of life.

The problems associated with disrupted development begin to manifest in childhood. One of the first behavioral hallmarks can be disrupted sleep. An April 2007 study demonstrated that even mild head injuries (such as those experienced during normal childhood bonks) increase the risk of sleep disorders.[15] In turn, these sleep disorders contribute to emotional distress[16] and have been demonstrated to contribute to disruptive behaviors in preschoolers. According to a June 1999 study, two and three year old children with sleep issues are “consistently at greatest risk for behavior problems such as oppositional or noncompliant behavior, ‘acting out’ behaviors, and aggression.” Not only do sleep disorders immediately lead to aggressive behavior, they coincide with suicide attempts later in life. A January 2007 study found that 89% of individuals who were admitted to medical units or psychiatric wards following a suicide attempt reported some type of sleep disturbance,[17] and a June 2007 study found that “as a warning sign, poor sleep quality constitutes a significant and modifiable risk factor for completed suicide.”[18] Neurological reorganization significantly improves sleep patterns, lowering the risk for self-directed violence and aggression.

Neuropsychiatric disorders symptomatic of disrupted development emerge in childhood. Disrupted central nervous system development is linked with childhood bipolar disorder, as demonstrated by a May 2006 study. As stated by the study author, “Our results also suggest that bipolar disorder likely stems from impaired development of specific brain circuits, as is thought to occur in schizophrenia and other mental illnesses.”[19] One of the hallmarks of this dysfunction is misreading neutral faces as hostile, leading to aggressive behavior in bipolar individuals. “Such a face-processing deficit could help account for the poor social skills, aggression, and irritability that characterizes this disorder in children.”[20] Neurological reorganization replicates the developmental sequence to insure that individuals read social cues appropriately and, hence, avoid the aggression and possible violence associated with misreading social cues.

Attention Deficit Hyperactivity Disorder (ADHD), another neuropsychiatric disorder associated with disrupted central nervous system function, often emerges in childhood. Amongst a range of emotional, academic, and behavioral issues, research has repeatedly linked childhood ADHD with alcohol abuse in the teen and adult years. Obviously, alcoholism greatly increases an individual’s risk for violence. “Children with ADHD are believed to be at risk for alcoholism because of their impulsivity and distractibility, as well as other problems that often accompany ADHD such as school failure and behavior problems[insert 4 periods with spaces between each one and between the words preceding and following.]We found that the children with ADHD were more likely than the comparison group to drink heavily and to have enough problems related to their drinking that they were diagnosed with alcohol abuse or dependence. This means that their drinking caused problems such as fights,” stated the lead author of an April 2007 study.[21] Not only does ADHD itself stem from central nervous system dysfunction, research demonstrates that a commonly prescribed ADHD medication, Ritalin, can cause central nervous system dysfunction itself. “[Children] placed on prescription drug therapy could face possible impaired brain performance as adults.”[22] Under certain circumstances, ADHD medication has also been linked to an increased propensity for narcotic use in early adulthood.[23] Neurological reorganization resolves the dysfunction that contributes to ADHD, hence minimizing an individual’s risk for alcoholism and related violence, without the side effects of medication.

Normal central nervous system development continues in adolescence.[24] An April 2007 study found that the brain changes that occur during adolescence cause even normally developing individuals to be “more susceptible to engaging in risky or dangerous behavior.”[25] If issues are already present from childhood, they only become worse during adolescence, as confirmed by a March 2006 study. “The effects of premature birth and environmental risks on the brain during the first three years of childhood continue through adolescence,”[26] especially in terms of appropriate social and behavioral regulation. Between the effects of normal adolescent brain changes and the results of disrupted early childhood development, teenagers are at high risk for the behavioral issues that lead to violence. Indeed, the June 2007 study confirming the high cost of violence found that the highest rates of violence occur among young men.[27] Addressing the underlying central nervous system dysfunction before these issues erupt in violence in adolescence is critical.

Trauma, either direct or indirect, also causes central nervous system dysfunction that can result in violence. Even if an individual successfully completed the developmental sequence, trauma damages brain function and results in the same constellation of high-risk behaviors as for individuals who did not complete the developmental sequence. A June 2002 study found that experience alters, neurologically, how individuals process emotion.[28] In the study, abused children were more likely to misinterpret facial cues as hostile and “exhibited more brain electrical activity than non-abused children when shown angry faces.”[29] This misinterpretation perpetuates violence, as a child could misinterpret an action or individual as hostile and respond aggressively. Furthermore, it demonstrates that the neurology of emotion is not innate but is informed by experience, a finding reinforced by a November 2000 study in which researchers stated quite simply “the strong association between exposure to violence and the use of violence by young adolescents illustrates that violence is a learned behavior.”[30] Also, a March 2007 study found that “a single, socially stressful situation can kill off new nerve cells in the brain region that processes learning, memory, and emotion, and possibly contribute to depression.”[31] Trauma alters central nervous system function and places an individual at risk for violence and aggression.

The idea that experience alters our neurological interpretation of emotion is confirmed by a March 2007 study that demonstrated that “humans acquire fears using similar neural processes whether they’ve personally experienced an aversive event or only witnessed it[insert 4 periods with spaces between each one and between the words preceding and following.]This finding demonstrates that similar neural systems are engaged where fears are learned through first-hand experience or by merely observing others.”[32] This applies to the neurological consequences of the observed violence in our society, especially when combined with the results of an April 2007 study regarding the roots of violence: “We easily recognize the living rooms and kitchens of sitcom characters but have never seen the inside of the home of the family living next door. We are increasingly isolated. A society that persists in creating a culture of isolation and disconnection may find itself in a very scary place. In extreme cases, people may lash out and hurt others.”[33] Between observed fears and increasing isolation, these studies reinforce the findings of an August 2004 study that “an estimated 30.8 million American adults meet standard diagnostic criteria for at least one personality disorder.”[34]

Potentially traumatic events are common for children.[35] Even without resulting in a diagnosis such as post-traumatic stress disorder, these traumas cause neurological distress and change that increase the child’s risk of violence. An incredibly common form of childhood trauma is bullying. Bullying has been found to effect 90% of children.[36] Additionally, bullying is not limited to the traditional perception of physical aggression but extends to more subtle social and emotional coercion. Bullying extracts long-term consequences and is linked to time spent in prison later in life, depression, anxiety, and suicide.[37] To further compound risk factors, children who already display disrupted development and central nervous system dysfunction in the form of obsessive-compulsive disorder (OCD) are three times more likely to be bullied than other children, and the taunts leveled at these children cause the symptoms of OCD to worsen.[38] In the course of daily life, most children experience minimal trauma, which extracts a central nervous system toll.

Children are inundated with violent media images. While it is controversial socially, research verifies that exposure to media violence has a significant negative impact on children and lends to aggressive and violent behavior. A March 2004 study found that “in the short-term, media violence can increase aggression by priming aggressive thoughts and decision processes, increasing psychological arousal, and triggering a tendency to imitate observed behaviors. In the long-term, repeated exposure can produce lasting increases in aggressive thought patterns and aggression-supporting beliefs about social behavior and can reduce individual's normal negative emotional response to violence.”[39] Researchers found that violence in video games, even in cartoonish video games geared towards children, leads to aggression and violence: “Habitual exposure to violent media [is] associated with higher levels of recent violent behavior[insert 4 periods with spaces between each one and between the words preceding and following.]Even the children’s violent video games – which are more cartoonish and often show no blood – had the same size effect on children and college students as the much more graphic games have on college students. What seems to matter is whether the players are practicing intentional harm to another character in the game. That’s what increases immediate aggression – more than how graphic or gory the game is.”[40] A June 2007 study also found that even cool, swift, and painless violence in PG-13 rated films teaches children “increased aggression, fear for their own safety, and a desensitization to the pain and suffering of others.”[41] Furthermore, an October 2006 study found that “toddlers and young children who watch violent movies, television shows or video games may be more likely to develop anxiety, sleep disorders, and aggressive and self-endangering behaviors.”[42] The average American child is exposed to thousands of acts of media-depicted violence by the age of ten, each of which increases his propensity for aggressive and violent behavior.

Research also links the observation of real-life, traumatic events with central nervous system changes that make one susceptible to violence. According to a May 2007 study, observing trauma changes neurological function in people who appear resilient and are not diagnosed with mental health issues. Significantly, at least half of the American adult population has experienced some sort of trauma that can contribute to depression, anxiety, and physical ailments. As stated by the lead author: “Our study suggests that there may be long-term neural correlates of trauma exposure, even in people who have looked resilient.”[43] Additionally, an April 2007 study found “repeated viewing of horrific images [such as 9/11] may result in increased levels of stress and trauma in the general population. And insofar as watching television replaces talking with others about such events, these undesired consequences may be amplified.”[44] These studies find that observation of traumatic events negatively impairs central nervous system function and can give rise to violence and aggression.

Of course, direct exposure to trauma results in a cascade of mental health issues that can lead to violence. An August 2003 study found that “children who witness their parents using violence against each other and who regularly receive excessive punishment are at increased risk of being involved in an abusive relationship as an adult[insert 4 periods with spaces between each one and between the words preceding and following.]In partner violence cases that result in injury, the study finds that being the victim of physical abuse and conduct disorders as a child are also important risk factors.”[45] Furthermore, witnessing domestic violence significantly increases a child’s likelihood of having asthma.[46] Trauma, such as a major natural disaster, also contributes to higher rates of central nervous system dysfunction indicative of propensity for violence. A May 2007 study found that post-traumatic stress disorder is ten times higher in residents of New Orleans following Hurricane Katrina than in the general public.[47] Not surprisingly, a June 2007 study found that “former military personnel are twice as likely to kill themselves as people who have not seen combat.”[48] Exposure to major trauma is a great predictor of later violence.

Neurological reorganization addresses the issues that contribute to aggression and violence through resolution of the underlying, central nervous system dysfunction. Regardless of the cause of the aggression and violence – disrupted development, trauma, or both – central nervous system dysfunction and altered brain processing occurs, giving rise to an array of high-risk behaviors. The same developmental sequence that should have put optimal function in place the first time can be replicated to regain function. Neurological reorganization recreates this developmental sequence to address the underlying, central nervous system basis of violence and aggression. We find that once a program of neurological reorganization is completed, clients no longer display the aggressive, violent, or at-risk behaviors that brought them to NNTC originally.

Clearly, the cycle of violence is self-perpetuating with the exposure to violence causing trauma which then gives way to increased likelihood for future violence. It is vital to stop this cycle and truly resolve the central nervous system component of it. Neurological reorganization is currently the only discipline that addresses these foundational, neurological aspects of violence.

[1] Phaedra Corso et al., American Journal of Preventive Medicine, June 2007.
[2] Ibid.
[3] Daniel Peterson, Ph.D., et al., The Journal of Neuroscience, March 14, 2007.
[4] Victor Carrion, M.D., et al., Released by Stanford University Medical Center, March 5, 2007.
[5] Seth Pollak, Presented at the Society for Psychophysiological Research, Fall 1998.
[6] Elbert Geuze, Ph.D., et al., Archives of General Psychiatry, January 2007.
[7] Nelly Alia-Klein et al., Presented at Center for Translational Neuroimaging, June 2007.
[8] Michelle Wirth et al., Physiology and Behavior, May 2007.
[9] Ronald Kessler, Ph.D., et al., Archives of General Psychiatry, June 2006.
[10] Lauretta Luck et al., Journal of Advanced Nursing, June 2007.
[11] Ann Bettencourt, Ph.D., et al., Psychological Bulletin, September 2006.
[12] Eero Kajantie, Annals of the New York Academy of Sciences, March 2007.
[13] Released by The Unit of Child and Adolescent Psychopathology, Universitat Autonoma de Barcelona, December 20, 2006.
[14] Yoko Nomura, Ph.D., M.P.H., et al., Archives of Pediatric and Adolescent Medicine, February 5, 2007.
[15] Liat Ayalon, Ph.D., Neurology, April 3, 2007.
[16] Ibid.
[17] Nisse Sjostrom, R.N., et al., SLEEP, January 1, 2007.
[18] Rebecca Bernert, Presented at SLEEP 2007, June 14, 2007.
[19] Dr. Ellen Leibenluft et al., Proceedings of the National Academy of Sciences, May 29, 2006.
[20] Ibid.
[21] Brook Molina et al., Alcoholism: Clinical and Experimental Research, April 2007.
[22] William Carlezon, Ph.D., et al., released at the American College of Neuropsychopharmacology, December 2004.
[23] Peter Thanos et al., Pharmacology, Biochemistry, and Behavior, June 5, 2007.
[24] Janice M. Juraska et al., Neuroscience, February 9, 2007.
[25] Laurence Steinberg, Current Directions in Psychological Science, April 2007.
[26] Michael Lewis, Ph.D., et al., Child Development, March/April 2006.
[27] Phaedra Corso et al., American Journal of Preventive Medicine, June 2007.
[28] Seth Pollak et al., Proceedings of the National Academy of Sciences, June 18, 2002.
[29] Ibid.
[30] Robert H. DuRant et al., Journal of Pediatrics, November 2000.
[31] Daniel Peterson, Ph.D., et al., The Journal of Neuroscience, March 14, 2007.
[32] Elizabeth Phelps et al., Social Cognitive and Affective Neuroscience, March 16, 2007.
[33] Glenn Sparks, Released by Purdue University, April 19, 2007.
[34] Bridget F. Grant, Ph.D., et al., Journal of Clinical Psychiatry, August 2004.
[35] William E. Copeland, Ph.D., Archives of General Psychiatry, May 2007.
[36] Tom Tarshis, M.D., et al., Journal of Developmental and Behavioral Pediatrics, April 2007.
[37] Ibid.
[38] Eric Storch, Ph.D., et al., Journal of Clinical Child and Adolescent Psychology, September 2006.
[39] Craig A. Anderson et al., Psychological Science in the Public Interest, March 2004.
[40] Katherine Gentile and Katherine Buckley, Violent Video Game Effects on Children and Adolescents, Oxford University Press, 2007.
[41] Theresa Webb et al., Pediatrics, June 2007.
[42] Dr. Daniel S. Schechter et al., Presented at the annual meeting of the American Academy of Child and Adolescent Psychiatry, October 28, 2006.
[43] Barbara Ganzel, Ph.D.., et al., Emotion, May 2007.
[44] Ruth Propper, Ph.D., Psychological Science, April 2007.
[45] Miriam K. Ehrensaft, Ph.D., et al, Journal of Consulting and Clinical Psychology, August 2003.
[46] S.V. Subramanian et al., International Journal of Epidemiology, June 2007.
[47] Lisa D. Mills, M.D., Presented at the 2007 Society for Academic Emergency Medicine, May 2007.
[48] Journal of Epidemiology and Community Health, July 2007.