Understanding Schizophrenia: a Biological Approach

NAME: Maria Saldias DATE: 4-28-2011

TITLES OF ARTCILES:
1-“ What Causes Schizophrenia”, by John M. Grohol, Psy.D.& the National Institute of Mental health12,Nov,2006.
2- “The Concept of Progressive Brain Change in Schizophrenia: Implications for Understanding Schizophrenia”, by Linn E. Delisi. 2008

INTRODUCTION
Schizophrenia is a brain disorder, which interferes with normal brain functioning. It is mainly characterize by major disturbances in perception, language, thought, emotions and behavior. Furthermore, it can also trigger hallucinations, delusions, paranoia, and lack of motivation (Rosenberg and Kosslyn). Experts now agree that schizophrenia develops as the result of the combination of a biological predisposition, and the kind of environment the person is exposed to. However, not until recent days, schizophrenia was thought to have “no “organic” cause and thus related to the psychological environment that one was born into” (Delisi).
In “What Causes schizophrenia, by Grohol, even though the author emphasis how genetic, behavioral and other factors, are interrelated in the development of the disorder, he emphasis his article in how the tools of biomedical research are being used to search for genes or critical moments of brain development.
At the same time, “The concept of Progressive Brain Chain in Schizophrenia: Implications for Understanding Schizophrenia”, by Delisi focuses in the new “discoveries” regarding brain change in schizophrenia, and how this ones support. Kraepelin perspective. The article states the different brain chances a schizophrenic patient goes through from its earliest stages to its chronic course.
Both articles are related to my topic in the way that they tide schizophrenia to biological factors.

REVIEW OF ARTCILE 1
Trough out the article, Grohol explores the different variants regarding the biological approach to the development of schizophrenia, by the use of modern biomedical research. In his first approach, the author refers to the genetic component of the disorder, where “multiple genes are involved in creating a predisposition to develop the disorder”. Grohol also emphasizes how factors such as prenatal and perinatal complications and other stressors can influence the development of the disease. Moreover, as regions of the human genome are being studied, the strongest evidence reveals that chromosomes13 and 6 may be responsible for carrying the susceptibility for developing schizophrenia.
The author also states how the disorder may be consequence of a chemical defect on the brain, more precisely the imbalance of the chemical systems of the brain, involving neurotransmitters such as dopamine and glutamate.
Finally, Grohol addresses the effects of the physical abnormalities in the brain, and how these ones can contribute to the development of the disorder, as there have been several studies of schizophrenic patients on which abnormalities in brain structure, such as enlargement of the ventricles and decreased size of certain regions of the brain, as well as functions, have been detected. Furthermore, Grohol also addresses how neurobiologists have found that schizophrenia may be a developmental disorder as a result of neurons forming inappropriate connections during fetal development.

REVIEW OF ARTICLE 2
In this article, Delisi provides a historical background of schizophrenia from Kreapelin’s writings and discoveries to recent times. It also reveals how the disorder shifted from being consider a non-biological disorder to a biological disorder, due to two discoveries addressing the effect on neuroleptics in suppressing symptoms as well as the family adoption studies, which show it was not environment, but rather inheritance what determine who develops or not the disorder.
Furthermore, the article addresses how studies using MRI (magnetic resonance imaging) and CT (computerized tomography), reveal a deviation in brain structural size in chronic schizophrenic patients and those at the first episode of illness, such as grey and white matter reductions, regional volume reductions, loss of normal asymmetries, miscellaneous developmental abnormalities and caudate enlargement, as a result of medication.
Later on the article, Delisi questions how much the progressive change observed in the brain of schizophrenic patients is related to the use of medication, as a study made with macaque monkeys after administrating them neuroleptics, revealed that there was a shrinkage in brain tissue.
Delisi also emphasizes the idea that reports and studies have proven that cortical brain changes are presented “prior to clinical illness presentation and even before any prodromal symptoms (an early symptom indicating a disease) emerge”, which leads to the conclusion that is possible to believe that progression occurs very early in some structures before patients are even identified as ill and then spreads to other regions of the brain.

ANALYSIS OF BOTH ARTICLES
As I already mentioned, schizophrenia is a brain disease, which was first described by Kraepelin as dementia praecox, at the end of the 19th century. Even though the disorder was first though to have no organic origins, both articles emphasize the biological an genetic components of the disorder due to new studies using computerized tomography, TC, and magnetic resonance imaging, MRI, on which ventricular enlargement (meaning that the brain size is reduced), grey and white matter reduction, regional volume reductions, such as frontal, temporal, hippocampus and other limbic regions, as well as the loss of normal asymmetries is revealed. Brain abnormalities in the hippocampus, for instance account for the deficits in memory. Defects in the frontal lobe, produced the elimination of neural connections. Moreover, these abnormalities in the brain also disrupted interactions among the frontal lobes, the thalamus and the cerebellum, which overwhelms subsequent processing, and the form and content of the person’s thoughts become confused (Rosenberg and Kosslyn). Even though the use of neuroleptics, antipsychotic medication use to manage psychosis, can have some sort of implications in the brain’s changes listed above, studies have shown that these abnormalities were previously shown in patients with the disorder.
In terms of the genetic predisposition, people who have a close relative with schizophrenia is more likely to develop the disorder than people with no schizophrenic history in their families. For instance, a monozygotic (identical) twin of a schizophrenic has the highest risk of developing the illness, (40 to 50 %); whereas a child whose parent has the disorder has about 10 % chance. By comparison, the risk of schizophrenia in the general population is about 1 percent.
Despite the fact the presence of genes are only a starting point, as the environment a person is exposed to play a fundamental role in developing schizophrenia, studies revealed that seven genes are more likely to be involved in the inheritance of schizophrenia. Furthermore, evidence suggests that multiple chromosomal regions are transmitted to people who are diagnosed with the disease (Psycentral.com).
Besides the inheritance component for developing the disorder, a study done in Finland, indicated that adopted children that had a high genetic/biological risk of schizophrenia (their mother had schizophrenia) had an 86% lower rate of developing schizophrenia when brought up in a healthy family vs a dysfunctional one. In healthy families, only 6 % of the children developed the disorder, whereas approximately 37% children develop it in dysfunctional families (Schizophrenia.com)
Lastly, chemical defects on the brain also play an important role in the development of schizophrenia. Neurotransmitters, substances that allow communication between nerve cells, have been thought to be associated with the development of the disorder. The dopamine hypothesis states that the behavioral patterns typical of schizophrenia are a result of over-activity of dopamine in certain regions of the brain (excessive dopamine activity can disrupt all aspects of motor, cognitive and emotional functioning and can result in an acute schizophrenic psychosis (dopamine has many functions in the brain, including important roles in behavior and cognition) (Grohol). In addition, developmental neurobiologists found the neurons forming inappropriate connections during fetal development may account for the risks of developing the disorder. This error usually remains dormant until puberty, when typical changes occurring in the brain at this stage of maturation interact with the faulty connection. This explains why schizophrenia’s symptoms are usually first expressed during adolescence or early adulthood (Delisi) In conclusion, the evidence and studies throughout all these years have revealed the interplay between biological predisposition and the kind of environment a person is exposed to as to be the cause of developing schizophrenia. In fact, experts now agree that schizophrenia and all other mental illness, is caused by a combination of biological, psychological and social factors, and this understanding of mental illness is what is called the bio-psycho-social model (schizophrenia.com). Further researches need to be done in order to finally identify which exactly genes are the ones involved (there is an hypothesis regarding chromosome 6 and 13, but is still unconfirmed) as it will provide clues in what is malfunctioning in the brain to produce and sustain the illness, while guiding the development of better treatments (Grohol).

Works Cited

Delesi, Lynn. “ The Concept of Progressive Brain Change in Schizophrenia: Implications for “Understanding Schizophrenia”. Schizophrenia Bulletin. Oxford Journals. 2008. Web. 10 April 2011.
Huffman, K. (2007). Schizophrenia . In K. Huffman, Psychology In Action (pp. 517-521). John Wiley & Sons, Inc.
Grohol, John M. “What Causes Schizophrenia?. Psycentral. Web. April 20 April 2011

Rosenberg, Robin and Kossyln, Stephen. (2010)Abnormal Psychology. Schizophrenia and other Psychotic Disorders. Worth Publishers.

“The Causes for Schizophrenia” Schizophrenia.com. Web April 20 2011 “What Causes Schizophrenia”. Psycentral.com. Web. 20 April 2011