Severe stress harmful to children's brain

A study conducted by researchers at the Standford School of Medicine and Lucile Packard Hospital found that severe stress can affect children's brain development, according to U.S. researchers. Although this finding had been replicated previously with animals, this was the first study of its kind conducted with children.

Children with PTSD and high levels of cortisol (a stress hormone released by the adrenal glands) were likely to experience a decrease in the size of the hippocampus, a brain structure important in memory processing and emotion.

The children in the study were suffering from post-traumatic stress disorder, or PTSD, as a result of undergoing physical, emotional or sexual abuse, witnessing violence or experiencing lasting separation and loss. This type of developmental trauma often impairs the child's ability to reach social, emotional and academic milestones.

The researchers studied 15 children from age 7 to 13 suffering from PTSD. They measured the volume of the hippocampus at the beginning and end of the 12- to 18-month study period.
After correcting for gender and for physiological maturity, they found that kids with more severe PTSD symptoms and higher bedtime cortisol levels (another marker of stress) at the start of the study were more likely to have reductions in their hippocampal volumes at the end of the study than their less-affected, but still traumatized peers.

The researchers speculated that cognitive deficits arising from stress hormones interfere with psychiatric therapy and prolong symptoms.

Children predisposed by genetics or environment to be more anxious than their peers are also more likely to develop PTSD in response to emotional trauma, perhaps because their responses to other life experiences simply left them closer to that threshold than less-anxious children, according to the study to be published in the March issue of Pediatrics.

There is no such thing as a "repressed memory"

A few nights ago, I shocked my class by making the statement, "there are no such things as repressed memories". People seemed quite bothered by that. I needed to leave early from the class, so I wanted to publish some of my musings on the issue.

First, why is the concept of "repressed memory" so important to a school psychologist (or, why is it important for a school psychologist to know that there is no such thing as a repressed memory?)? It has particular relevance in cases of suspected or alleged physical and sexual abuse. It is important for school psychologists to understand how memory works and why the repressed memory is an urban psychological myth.

Second, let's get some clarity:

• A repressed memory, according to some theories of psychology, is a memory (often traumatic) of an event or environment which is stored by the unconscious mind but outside the awareness of the conscious mind.
• Some theorize that these memories may be recovered (that is, integrated into consciousness) years or decades after the event, often via therapy. They may also reoccur in dreams.
• The idea of "dissociative amnesia" makes the assumption that memory repression is possible. The repressed memory concept was popularized during the 1980s and partly the 1990s by the popular press, some feminist groups, and some psychological schools of thought
• The concept was originated by Sigmund Freud in his 1896 essay On the etiology of hysteria.
  Freud abandoned his theory between 1897-1905, and during 1920-1923 replaced it with his impulse-based concept of Id, Super-ego, and Ego.

There were two principle reasons that Freud abandoned his theory of repressed memory (Freud, Sigmund 1952. Zur Geschichte der analytischen Bewegung, from: Gesammelte Werke in Einzelbänden Volume 10)

• he increasingly came upon evidences in individual cases logically outruling any possibility the 'recovered' events could have occurred
• he found himself able to direct his more suggestible patients into any recollection of memory he wanted to (especially while they were undergoing hypnosis), even more so in an entirely boundless manner when he turned to sexual matters.

This is an important set of points, as the father of psychoanalysis, quickly retracted the construct of "repressed memory" for the same reason that modern researchers have also rejected this notion.

Third you may ask if there is there any scientific basis for the construct of a "repressed memory"? Well, there are some conjectures and possibilities. For example, one theory discusses how the hippocampus may selectively choose to not consolidate memories which are traumatic. Others point to the role of cortisol damage to the hippocampus. These "hypotheses" are explored in Faigman DL, Kaye DH, Saks MJ, Sanders J, eds. Science in the law: social and behavioral science issues. St. Paul, MN: West Group, 2002, pp 487-526.

I will tell you how it all turns out. These are just conjectures which don't make sense on any level neurologically.

Cortisol does indeed cause damage to the hippocampal structures and loops, but it does not erase traumatic events. In fact, what we have identified in PTSD is that many people have re-occurrences of the traumatic event, so the event memory is on a constant rewind. And, while cortisol damage may affect the person's accurate recollection of the trauma, there will still be a recollection that the event took place.

Studies of over than 10,000 trauma victims found none that repressed or recovered memories of trauma. (Pope HG Jr, Oliva PS, Hudson JI. Repressed memories. The scientific status of research on repressed memories. In: Faigman DL, Kaye DH, Saks MJ, Sanders J, eds. Science in the law: social and behavioral science issues. St. Paul, MN: West Group, 2002, pp 487-526). Similarly, some studies of thousands of abused children found no evidence at all for so-called repressed or recovered memories. Coupled with laboratory studies and other naturalistic investigations, most prominent researchers in the field agree with Harvard University's Richard McNally and consider the notion of repressed memory to be a pernicious bit of psychiatric folklore. (McNally RJ. The science and folklore of traumatic amnesia. Clinical Psychology: Science and Practice 11:29-33, 2004).

Then we get to young children. Young children's memory is incredibly inaccurate, as their hippocampal structures are developing from conception until about three years old. Although they may forget (I've blogged on this before), they do not "repress" the memory - they just developmentally cannot consolidate memories effectively and cannot recall them effectively.

Another difference is actual amnesia following a trauma. This is not due to any psychic events impinging upon mental makeup. Retrograde amnesia is a real neurological issue which comes about through some physical assault to the brain which causes hippocampal structures to temporarily (or in some cases permanently) not recall as effectively or efficiently. The important aspect of retrograde amnesia is that it is caused by physical etiologies and not by psychic or psychological etiology.

Later I will discuss some court cases which have impacted this area.

Babies do form memories; they just forget...

The AP reports that babies' rate of forgetting is even faster than that of adults, this quote taken directly from Patricia J. Bauer of Duke University said Friday at the annual meeting of the American Association for the Advancement of Science.

Bauer was part of a panel discussing "infant amnesia," the puzzling inability of people to remember events early in life.

Previous neuropsychological orthodoxy stated that babies' brains were simply unable to form memories, but Bauer said new research indicates that is incorrect; this was due to the fact that the hippocampal structures were not solidly developed at such a young age (they tend to solidify at age 3).

The ability to form memories depends on a network of structures in the brain and these develop at different times, Bauer said. As the networks come together between 6 months and 18 months of life, researchers see increased efficiency in the ability to form short-and long-term memory, she said.

From age six months to two years, memory increases from about 24 hours to a year researchers stated. But, noting that children, like adults, forget, she compared the brains of infants and adults to colanders used to drain food. The adult colander has small holes, for draining something like orzo or rice, while the infant colander has larger holes, such as for draining large penne pasta, but allowing more information to flow out.

Bauer's research proceeded by testing infants by using objects such as cups and blocks. In one test a baby would be shown two cups, a block would be put into one, the other cup would be put over the top and the group would be shaken to form a rattle.

This is something children do not do instinctively, she explained, but once they see it they can copy it, and researchers can see how long they remember when given the same objects.
Oakes said she studied infants by watching how long they would look at something. Babies will look longer at something new than something they are familiar with, she said, which allows researchers to calculate how long the baby remembers something.

Tracy DeBoer of the University of California, Davis, said babies born to diabetic mothers are at increased risk of memory loss. Such children may have shortages of oxygen and iron before birth and that can cause impaired memory when they are growing. That impairment did not occur in cases where the mothers' diabetes was controlled during pregnancy, she added.