Literature review of four articles to support hypothesis
Auwera, S. V., Janowitz, D., Schulz, A., Homuth, G., Nauck, M., Völzke, H., Grabe, H. J. (2014). Interaction among childhood trauma and functional polymorphisms in the serotonin pathway moderate the risk of depressive disorders. European Archives of Psychiatry and Clinical Neuroscience, 264(S1), 45-54.
In this dual case study, Auwera and coauthors worked to find the interaction, if any, between childhood abuse (i.e., trauma) and incidence of genetic polymorphisms causing serotonergic dysfunction. In order to assess this interaction, the authors tested for genetic polymorphisms in TPH2, a serotonin limiting enzyme, and 5-HTTLPR, a serotonin reuptake transporter, as well as depression severity (via the Beck depression inventory, BDI) and severity of childhood trauma. The results of the study supported the hypothesis that genetic variants that cause serotonergic dysfunction at synapse are associated with depressive symptoms in individuals whom experienced child abuse. While this study does not draw a comparison between depressive symptoms in individuals with childhood trauma and individuals without childhood trauma, it does show the existence of a relationship between childhood abuse and genetic variants within the serotonergic system. This will be useful as it suggests that onset of depressive symptoms is impacted by both genetic and environmental factors and that there is interplay between them, the effects of which being measureable.
Berglund, K. J., Balldin, J., Berggren, U., Gerdner, A., & Fahlke, C. (2013). Childhood Maltreatment Affects the Serotonergic System in Male Alcohol-Dependent Individuals. Alcoholism: Clinical and Experimental Research, 37(5), 757-762.
In this study, author K. J. Berglund and coauthors explore the relationship between childhood maltreatment and central serotonergic neurotransmission. The study used statistical methods to compare activity in the serotonergic system (measured by a neuroendocrine method involving prolactin response to selective 5-hydroxyltransferase reuptake inhibitor citalopram), alcohol dependence (diagnosed by outpatient treatment units) and childhood maltreatment (diagnosed by Childhood Trauma Questionnaire). The findings show that emotional abuse in alcohol-dependent individuals is correlated with a dramatic reduction in central serotonergic neurotransmission. This article will be useful to me in that it supports the existence of an interaction between trauma and development of psychological behaviors associated with serotonergic dysfunction (in this case, alcohol dependence). It is important to note however that correlation does not prove causation; the childhood maltreatment may not be the cause of the serotonergic dysfunction. It does, however, exemplify the relationship between neurobiological ailments and social consequences, and potential interplay between neural dysfunction, psychological ailment, and sociocultural stigma associated with alcohol dependence.
Donnelly, C. L. (2003). Pharmacologic treatment approaches for children and adolescents with posttraumatic stress disorder. Child and Adolescent Psychiatric Clinics of North America, 12(2), 251-269.
In this article, author C.L. Donnelly compiles data from a variety of sources to elucidate and interpret the effects of pharmacological treatment of PTSD in adults and children, the effectiveness of that treatment, and the types of treatments that the psychiatric community deems most useful. In his findings, the author finds that selective serotonin reuptake inhibitors (SSRIs) are the most generally effective pharmacological treatment, as the impact a majority of depressive and/or anxious symptoms associated with PTSD. He also finds that “children seem to be more sensitive to the effects of trauma,” which could be related to the formative effects of trauma. This article will be useful to me in that it shows that the serotonergic system is related to trauma, and that serotonergic dysfunction is related to the depressive and anxious symptoms associated with trauma. This article also supports my portfolio’s position that there is a distinct difference between a child’s sensitivity to trauma to that of an adolescent, and that this difference could be explained by the formative effects of trauma on the serotonergic system.
Murrough, J. W. (2011). The Effect of Early Trauma Exposure on Serotonin Type 1B Receptor Expression Revealed by Reduced Selective Radioligand Binding. Archives of General Psychiatry, 68(9), 892.
In this study, Murrough and coauthors researched the relationship between disturbances in the function of serotonin-type 1B receptor and the incidence of chronic anxiety in PTSD patients who experienced trauma in early childhood. To study this relationship, the authors used PET scans to observe differences in serotonin type 1B receptor expression between trauma-exposed individuals and non-trauma exposed control individuals. The findings showed that a “history of severe trauma exposure” in the PTSD group was related to “marked reductions in the caudate, the amygdala, and the anterior cingulate cortex”, and that the age of the individual was strongly associated with low expression of the serotonin-type 1B receptor. These findings suggest that there is a strong relationship between trauma and brain function, and that early traumas result in more “pronounced neurobiological and behavioral alterations in PTSD”. This article will be useful to me as it supports the hypothesis that trauma impacts the serotonergic system of the brain and that the earlier the trauma, the more pronounced the effects on the serotonergic system. The study included neuroimaging techniques that allow researchers to view the anatomical effects of trauma on the brain, as opposed to just observing it through psychological symptoms. This will be useful in supporting the claim that the genetic components of psychological disorders associated with trauma can be impacted by environmental components, and therefore trauma has a formative effect on the development of the serotonergic system within the brain.
Summary:
These articles provide background as well as evidence to support my hypothesis that childhood trauma has a developmental impact on the serotonergic system of the brain. Articles such as those written by Auwera et al. (2014). Berglund et al. (2013) and Donnelly (2013) show that psychological ailments associated with trauma are associated with serotonergic dysfunction in both adults and children, and that SSRIs are typically the pharmacological treatment of choice to treat the symptoms of psychological ailments associated with trauma. The article by Murrough (2011) shows that there is a neurobiological difference in the expression of certain neurobiological factors associated with proper serotonergic function, and that the timing of the trauma can have an impact on the development of said neurobiological factors. These articles together show that childhood trauma impacts the serotonergic pathway on a neural level, and that timing of childhood trauma can affect the severity of that impact, which is observable through neuroimaging techniques as well as observance of post-traumatic stress and alcohol-dependent disorder phenotypes. Also, these articles will help me to support or refute my claims regarding the interplay of genetic, environmental, and chronological factors on the development of psychological disorders related to serotonergic dysfunction.