Child Trauma and the Hippocampus

mcurrie's picture

 

            Post traumatic stress disorder (PTSD) has been more commonly noticed in soldiers who have experienced high levels of stress during war. Children during traumatic events may also develop post traumatic stress disorder and the effects of the traumatic event are more complex. Between children and adults, children are 1.5 times more likely to get PTSD than adults.8 PTSD arises due to increased levels of stress during an event that places people in a frightening, life-threatening, or unsafe experience and they lose their feeling of comfort and safety. This event may include survival in environmental disasters, violent crimes (kidnapping), witnessing a death, etc.5 In children PTSD can be detrimental to their social life in being unable to trust another person and leaves them on high alert to their surroundings in order to try and avoid any dangers that will lead to more fear and insecurity. A child who has PTSD may have an overwhelming fear of specific objects, sounds or surroundings, sudden panic, regression in behavior, loss of acquired developmental skills, and slowdown in language development.4

            In a child, the level of PTSD can be affected by the time of the traumatic event and the location.8 A child could have a stronger reaction to a stressful event in a place where the child feels the most safe and comfortable. Time of the event is important due to the time of brain development of the child that the traumatic event occurs, like myleination of neurons, neurogenesis, and synaptic pruning. Depending on the time of development different sections of the brain could be affected more than others. When a child experiences a traumatic event the increased stress can be detrimental to the growth of a well developed brain. In order to cope with a traumatic experience, a child will use posttraumatic play by acting out certain aspects of the traumatic event. For example a little boy used a doll to act out the time when he found his murdered mother, although the little boy changed to ending with the doll being able to save his mother from death.4 With posttraumatic play children do not act out all of the details of the event probably due to the children being unable to remember every detail.

             Treatments for PTSD have ranged from therapy to medications in order to help children cope with their traumatic events and the effects of increased stress on the brain and body. These treatments are also used to help children heal. The treatments include cognitive behavioral therapy, play therapy, and medications like Adderal, Prozac, and Abilify.

            A child who has PTSD has been shown to have less developed frontal cortex and sections of the corpus callosum and appear to have smaller brain volumes. The frontal cortex function is to recognize incoming stimuli, plan appropriate behavior responses though motor stimulus, and also interacts with portions of the brain that are related to learning and memory. When the frontal cortex is damaged an individual has been shown to exhibit personality changes and impairment in planning.9 With children the damage of the frontal cortex could account for regression in certain behaviors. The corpus callosum connects the left and right brain which could affect the interactions between the sides of the brain.5 MRI, magnetic resonance imaging, has also accounted for a decrease in white and gray matter.8

            Another portion of a child’s brain that could be affected by PTSD is the hippocampus. The hippocampus plays a role in learning and memory. In adults the hippocampus is decreased due to high levels of glucocorticoids which is toxic to the hippocampus, while children with PTSD do not have high levels of glucocorticoid, and studies of children have shown that the size of the hippocampus is not affected by PTSD. Although glucocorticoids is not found in children it does not mean that the hippocampus in not affected in children with PTSD. The hippocampus could still be a smaller size in children with PTSD but the size may be too small due to the hippocampus’s continued development or increase in volume until a person reaches twenty.8 The change in the hippocampus can be difficult to measure since every child develops differently so there is no easy way to compare the change in size of the hippocampus of children with or without PTSD.

            Children and adults with PTSD can develop amnesia in order to try and avoid remembering the traumatic event. This could be due to a decrease in the hippocampus which results in the shutting down of neurons or the dysfunction of neurons due to a decrease in volume. In a study the hippocampus activation and volume were measured in women who were sexually abused in their childhood and had PTSD, women who were abused without PTSD, and women with no abuse and no PTSD. The women who were abused with PTSD had less activation of the hippocampus and a smaller sized hippocampus compared to women who were abused with no PTSD and women that were not abused.1 With PTSD children’s hippocampus may not seem affected as they grow until they reach adulthood or the hippocampus is fully developed like the women who were abused as children with PTSD. Once the children are adults the change in the hippocampus volume could be more easily measured along with the decrease in activation due to a decrease in size.

              Or the change in volume of the hippocampus in children could be a result of medication or drugs used throughout their childhood and into adulthood in order to help them cope with the symptoms of PTSD. In the experiment some of the women had a history of substance abuse and drinking although medications for other symptoms were not included.1 But medications that affect neurons within the brain such as antidepressants, guanfacine which is used to treat flashbacks, anti-anxiety pills, and ADHD medications could also affect the hippocampus in suppressing memories or harming the development of a child’s brain. Plus children without PTSD could be taking medications, like Adderal for ADHD, that could also result in decreased size of the hippocampus, although the size may be insignificant, making it harder for the size of the hippocampus to be seen and compared to children with PTSD. For children with PTSD it has been found that the total size of their brains are smaller than children without PTSD.8 There are portions of the brain that have been shown to decrease in children, like the frontal cortex or the campus callosum. These sections of the brain can contribute to the total volume of a child’s brain, but there is still the possibility that a small percentage of the total loss in brain size could be accounted for by a decrease in the hippocampus volume. Another study of children with PTSD has found that the children have a decrease in function of the hippocampus. Using magnetic resonance imaging, MRI, children were given simple verbal memory tests as their brains were scanned.2 Although the size of the hippocampus may be difficult to measure the function of the hippocampus is a part of the brain that can be affected by PTSD in children. Therefore further study should be performed to increase the knowledge of the hippocampus in children with PTSD in order to figure if function of the hippocampus in children is due to a decrease in size or not.

            PTSD research still has a lot to study and expand on their knowledge of how PTSD affects children’s neurology. In many of the experiments there has been an insufficient “control” or not enough children who were studied that do not have PTSD. The lack of data to compare children with and without PTSD can affect the interpretations of the changes in development of a child’s brain. With more research the effects of PTSD on the hippocampus can be expanded and changed with more information on the development of the brain with children who have PTSD and children without PTSD.

References

1)      Bremner, Douglas J et al. (2003, May ). MRI and PET study of deficits in hippocampus    

       structure and function in women with childhood sexual abuse and posttraumatic   

       stress disorder. The American Journal of Psychiatry; 160, 5; Research Library pg. 924

2)   Fisher, Chris. (2010, January 12). Brain imaging shows kids' ptsd symptoms

      linked to poor hippocampus function. Retrieved from  

      http://www.bmedreport.com/archives/8580

3)   Hamblen, Jessica. (2008, August 6). Ptsd in children and adolescents.

      Retrieved from   

      http://ncptsd.va.gov/ncmain/ncdocs/fact_shts/fs_children.html

4)   Monahon, Cynthia. (1993). Children and trauma: a guide for parents and

      professionals. San Francisco, Ca: Jossey-Bass Publishers.

5)   N/A, . (2010). Anatomy of the brain: corpus callosum. Retrieved from

      http://biology.about.com/library/organs/brain/blcorpus.htm

6)   N/A. (1996). Posttraumatic stress disorder. Retrieved from

     http://www.medicinenet.com/posttraumatic_stress_disorder/article.com

7)   N/A,. (2004). Psychiatric medication for children and adolescents: part ii -  

       types of medications. American Academy of Child and Adolescent

       Psychology, 29. Retrieved from

http://www.aacap.org/cs/root/facts_for_families/psychiatric_medication_for_children_and_adolescents_part_ii_types_of_medications

8)      Silva, Raul R. (2004). Posttraumatic stress disorder in children and

      adolescents. New York, NY: W.W. Norton and Company.

9)      Tamminga, Carol, & Buchsbaum, Monte S. (2004, December). Imaging of

      neuroscience: frontal cortex function. Retrieved from

      http://ajp.psychiatryonline.org/cgi/reprint/161/12/2178.pdf

   

Comments

Paul Grobstein's picture

PTSD and brain research

"PTSD research still has a lot to study and expand on their knowledge of how PTSD affects children’s neurology."

Undoubtedly.  But this account also makes me wonder why researchers focus on particular aspects of the matter (eg the hippocampus) and to what extent that reflects what researchers know something about rather than any wider interest in/familiarity with PTSD as a more general clinical or conceptual problem.  In what ways would knowing more about the relation between PTSD in children and hippocampal size be significant either clinically or conceptually? 

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