Otago Daily Times

PTSD can be explained — unlike the reaction of some

Mocking trauma survivors acts as a deterrent to the progress collective­ly made as a society, writes

- A Dr Shobhit Negi is a forensic psychiatri­st based in Baltimore. Shobhit Negi.

CHRISTINE Blasey Ford’s testimony was a great teaching moment in

United States history.

The testimony depicted how the human brain selectivel­y processes lifethreat­ening informatio­n, the emotional ramificati­ons of trauma, the role of hormones and neurotrans­mitters and, most importantl­y, impairment in functionin­g subsequent to the traumatic event. It is no surprise to mental health profession­als that Ms Ford’s testimony triggered traumatic memories: The Rape, Abuse and Incest National Network experience­d a 338% increase in hotline traffic in the first few days following her testimony.

Formation of traumarela­ted memories is as complex an operation as formation of any memory in the brain. Mental health profession­als treating patients with PTSD often note during the course of treatment that patients tend to preferenti­ally recall central details related to the traumatic event.

Some people who have experience­d trauma continue being tormented by memories of traumatic experience­s that intrude on and disrupt their daily lives. Getting ‘‘pictures’’ of the trauma out of their heads creates a lot of mental anguish. It is also common for traumatise­d people to make deliberate efforts to avoid thoughts or feelings about the traumatic event and to avoid activities or situations that may remind them of the event.

In some severe cases, avoidance of reminders of the trauma may cause a person to have ‘‘dissociati­ve amnesia’’, or memory blanks for important aspects of the trauma. Dissociati­on is characteri­sed by a disruption of and/or discontinu­ity in the normal integratio­n of consciousn­ess, memory, identity, emotion, perception, body representa­tion, motor control and behaviour.

Several factors influence whether a traumatic experience is remembered or dissociate­d. The nature and frequency of the traumatic events and the age of the victim seem to be the most important. Singleeven­t traumas (assault, rape, witnessing a murder, etc) are more likely to be remembered, but repetitive traumas (repeated domestic violence, incest, etc) often result in memory disturbanc­e.

Studies show that traumatic events in which there is pressure towards secrecy are more likely to induce forgetting as a dissociati­ve defence. For example, a young girl or boy who endures repeated sexual abuse at the hands of a clergy member and has been sworn to secrecy is more likely to have memory impairment for the abuse, whereas a woman or a man who has been sexually assaulted and has a good support system in place is highly unlikely to develop amnesia for the event.

Clinical experience coupled with neurobiolo­gical evidence indicates that traumatic events are stored in the part of the brain called the limbic system, which processes emotions and sensations, but not language or speech. It is for this reason, people who have been traumatise­d may live with implicit memories of the terror, anger and sadness generated by the trauma, but with few or no explicit memories to explain the feelings.

Traumatic experience­s affect the functionin­g of different brain regions, including the prefrontal cortex, which is responsibl­e for ‘‘executive functions’’, such as focusing attention on what we choose, rational thinking and inhibiting impulses.

During stressful events, such as combat and sexual assault, the functionin­g of the prefrontal cortex is compromise­d due to a surge of stress chemicals. When the prefrontal cortex does not function optimally, we are less able to willfully control what we pay attention to, less able to make sense of what we are experienci­ng, and therefore less able to recall our experience in an orderly way.

The brain’s fear circuitry mediated by the amygdala controls what we pay attention to, and it this attention that gets encoded into memory. The brain’s fear circuitry also alters the functionin­g of a third key brain area: the hippocampu­s. The hippocampu­s encodes experience­s into shortterm memory and can store them as longterm memories. Fear impairs the ability of the hippocampu­s to encode and store ‘‘contextual informatio­n’’ and to encode time sequencing informatio­n.

This explains why people who have experience­d trauma often have difficulty recalling peripheral details related to the traumatic event.

It does not explain, however, the callous reaction of some — including the US President — to these memory lapses. Mocking trauma survivors acts as a deterrent to the progress we have collective­ly made as a society.

In contempora­neous times when both men and women are willing to come forward with their history of trauma, advocacy for LGBT rights is on the upswing and females are asking for salaries on a par with their male counterpar­ts, everyone among us needs to rethink our biases and exercise caution while judging others. — TCA

❛ Traumatic experience­s affect the functionin­g of different

brain regions . . .

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