The violent reflex

Grafik: MW
Auswirkungen von Gewalt auf das Gehirn während der Pubertät
Author: Susanne Donner

Repeated experiences with violence become engraved in the brain. This makes such experiences an important risk factor for a number of psychological disturbances.

Scientific support: Prof. Dr. Kerstin Konrad

Published: 13.04.2017

Difficulty: intermediate

At a glance
  • Experiences of violence are a risk factor for psychological illness. However, not everyone who has them develops an illness.
  • Statistically speaking, evidence for violence in an earlier generation of a family can be observed in later generations.
  • Posttraumatic stress disorder develops when an act of violence in a life-threatening situation is preserved without its time and spatial context, in a way that allows it to be reactivated through the most trivial stimulus.
  • The brain and the expression of genes are changed through prior exposure to violence.
  • The mental changes that occur in response to violent experiences can be undone, at least to some extent.
Combustion point: too many young men

The fact that Sociologist Gunnar Heinsohn is a man takes a bit of the bite out of his critique of his own sex: the wars and bloody conflicts of world history, he believes, can largely be explained by the presence of too many young men. If at least 30 percent of a society lies between the ages of 15 and 29, he argues, then violent conflicts are quick to arise. This was the case not only prior to World War I but also for the conflicts in Afghanistan, South America and Iraq. Because such societies do not have enough positions for young men to provide for their families, the result is war. World views and religion are simply used as excuses to justify the killing, Heinsohn claims.

The Berlin demographer Steffen Kröhnert claims that Heinsohn's thesis is oversimplified, pointing out that the likelihood of war has not always risen with an excess in the population of young men. At times when they were parents themselves, this was seldom the case. More to the point are the poverty and poor development of countries that are rife for conflict – in such cases, then an excess of young men adds to the potential for a crisis.

In the face of a life-threatening situation, a person is completely out of control and acts without reflection. It is impossible to capture such irrational moments in words – they are best forgotten. But fear and shock linger on and can be awakened by the tiniest of stimuli. The affected person enters a state of shock, becomes pale, sweats over the entire body, and sometimes completely collapses.

Violence that reaches into the present

Soldiers in the Second World War reacted to their wartime experiences in quite individual ways, according to a 2010 study by Gereon Heuft and Gudrun Schneider of the University of Münster. Their work was based on interviews with 122 children of World War II who had been born between 1930 and 1945.

"32 percent of the interviewees still consider these experiences a heavy burden to the present day," Schneider reports. "On the other hand, that means the rest do not regard these situations as traumatic." Her conclusion: one shouldn't assume that every person who has experienced violence is traumatized per se. "The same event can be experienced in very different ways," Matthias Grundmann says. One can't predict whether a war experience will lead to a psychological burden that lasts throughout a person's life.

In other words, not everyone can be lumped together – even so, terrible experiences tend to become a burden for a person's later development. This finally became undeniable for psychiatrists after the Vietnam War, through the many soldiers who had departed for the conflict in good mental health; upon their return, they were unable to adjust. They couldn't connect to former friends. Some poor souls relived horrible scenes over and over in flashbacks; some took their own lives. Their doctors had to accept the fact that violence often leads to mental illness.

And evidence for this connection is apparent today. Doctors and psychiatrists who examined Syrian refugees have sounded the alarm once again. Child psychologist Enrico Ullmann of the University Clinic of Dresden discovered that one out of every two subjects fit the criteria for posttraumatic stress syndrome. Other studies have placed the figure at 30 percent or higher.

A multi-generation effect

"These effects last for several generations," says Günter Seidler, Head of the Psychotraumatology Unit at the University of Heidelberg and a pioneer in German trauma research. A number of studies have confirmed his statement: 149 people imprisoned in the former GDR have unusually high rates of depression and anxiety even 20 years after the fall of the Berlin Wall. These feelings are typically the result of traumatic experiences. The symptoms include an increased sensitivity to pain and physical complaints and poorer patterns of sleep. When their children were investigated, 43 turned out to be less psychologically stable, although over generations the after-effects of the trauma underwent a reduction.

Most studies have shown that women are particularly sensitive to violence. This was one result of an analysis carried out by Psychologist Michelle Slone of Tel Aviv University. She gave a questionnaire to 9,000 Israeli youth between the ages of 12 to 17 years, in search of psychiatric disorders, and subsequently followed them over a period of 14 years. During this time the subjects experienced war, attacks, and air assaults. She compared the subjects in her home country with a control group in the USA who had grown up mostly without violence. The Israelis, particularly the young women, exhibited higher rates of anxiety, depression, compulsive disorders and paranoia.

What happens in the brain

A life-threatening situation causes the body to release massive quantities of the stress hormones cortisol and adrenaline, says trauma researcher Seidler. They especially affect the hippocampus in the brain and cause an act of violence to be remembered in an unusual way. Space and time coordinates are lost, which means that the tiniest trigger can reactivate the memory. At that point the horror is relived as if it is real, in the moment – making a trauma a lasting state of shock for the brain.

"Experience of violence make us someone else," says Neuropsychologist Thomas Elbert of the University of Konstanz. "The entire organism – particularly the brain – is tuned to a fight mode." Elbert distinguishes between reaction modes for peace and for threats. Suppose a black cable is lying on the ground across a path into a moor – a hiker might mistake it for a snake. Under normal circumstances the person would look again and, after the first moment of panic, realize that it is just a cable. But if it truly were a poisonous snake, that delayed reaction could be a disadvantage. A person in fighting mode would grab a stick and strike the presumed animal, or jump quickly to one side. "What is perceived is directed very quickly to the limbic pathway in the brain: A person's immediate reaction is emotional, and then comes the physical," Elbert says.

He observed this difference in thinking in experiments based on magnetic resonance tomography. Using the so-called Diffusion Tensor Imaging Mode, he watched the most important pathways between nerves – the "data highways" of the brain. Further research using MRT showed that when traumatized patients and control subjects were shown images of violence in rapid succession, the patients tended to become upset. Regions of the brain that govern fear became active. At the same time, motor centers were triggered; the patients wanted to act. "Such a person is well prepared in times of crisis, because he or she is quick to act," Elbert says. "But in times of peace they hit the ceiling. Sometimes the smallest thing can set them off, causing them to strike, which causes problems." Thus a person who is raised in a context of violence tends toward violence later.

Violence changes the way genetic information is read

In parallel to the restructuring that has been observed in the brain, scientists have also detected a number of changes in the genome that accompany violence. Environmental influences can write themselves into the genetic code by changing patterns of methylation and the way regions of DNA are read. This causes important alterations in the molecular interpretation of the blueprint of life. Physicians can't study these changes, however, because by the time they see patients, the subjects have already been the victims of trauma.

So scientists seek answers through analogy, by studying what Elbert calls "the strongest cause of stress in the animal kingdom by far." Monkeys or other experimental animals are taken from the mother after birth and raised with other young aninmals. Young rhesus monkeys that have been exposed to this practice evidenced much larger stress networks in their brains, says Simona Spinelli, who has worked at the Johns Hopkins School of Medicine in Baltimore since 2009. This might explain why humans who experience stress and violence in their childhood and youth are at higher risk of developing psychiatric illnesses later in life. In 2012 Nadine Provencal of McGill University in Montreal carried out a study on makaws and showed that animals raised without their mothers exhibited changes in methylation patterns in 6000 genes. "That represents a fifth of their total number of genes," Elbert says. "And as a result, a completely different animal."

Genes that had functions in stress responses were particularly affected. One of the changes led to an increase in the release of a protein with the unwieldy name "Proopiomelanocortocoid." This molecule powerfully reduces the amount of pain a person feels during a fight. Elbert's team found this change in 35 traumatized children in Tanzania as well.

Trauma is a thing of the past

Researchers and therapists are divided over the question of whether a traumatized person can ever fully be cured. "To a certain degree, psychotherapy can undo the changes," the scientist from Konstanz says. The brain has a degree of plasticity that can permit it to learn to localize the trauma in the past. Even epigenetic changes can partially disappear in the aftermath of therapy," he says.

But without such help, Seidler says, things look grim for people in societies such as Iraq, Afghanistan and Syria that have been rocked by war. The danger is that mass trauma makes conditions favorable for violence in future generations.

And yet each individual possesses resources that can offer protection from the aftereffects of trauma, Seidler says: intact ties with friends and family count, as do ideological convictions such as religious beliefs. 

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