Furii’s Flaming Finger’s

(A.K.A.: Team 1)

Possible Causes of Schizophrenia

By: Andrew, Anne, Connie and Diana

Genetics - Interplay

   Experts now agree that schizophrenia develops as a result of interplay between biological predisposition (for example, inheriting certain genes) and the kind of environment a person is exposed to (schizophrenia.com).

Schizophrenia researchers break down the causes of schizophrenia into two categories:   Genetic(s) (schizophrenia.com) Environment (everything other than genes) (schizophrenia.com).:  “Social, nutritional, hormonal and chemical environment in the womb of the mother during pregnancy, up to the social dynamics and stress a person experiences, to street drug use, education, virus exposure, vitamin use, and much, much more” (schizophrenia.com).

Another way to think of this is “Nature vs. Nuture” or “genes vs. environment” (schizophrenia.com).

Genetics - Examples

  An example of how a genetic predisposition for schizophrenia can be triggered by environmental influences can be seen in a research study taken from Biological Psychiatry, Volume 57:  Indicates that people who had multiple copies of a version of the COMT gene and who smoked marijuana had a 1,000% increase in their risk of developing schizophrenia (as cited on schizophrenia.com).

Another example from the British Journal of Psychiatry:  Indicates that adopted children with high genetic/biological risk for schizophrenia (their mother had schizophrenia) had an 86% lower rate of developing schizophrenia raised in a healthy vs. a dysfunctional family. Only 6% of the children developed schizophrenia in the healthy family. 37% of the children of the dysfunctional families developed schizophrenia (as cited on schizophrenia.com).

Genetics - Research

     There are multiple genes being researched right now that may be contributing to the schizophrenia. There are about a dozen that are the leading contributors (schizophrenia.com).

There is also research being done to investigate what biological molecules may be responsible for turning on and off certain genes contributing to schizophrenia (schizophrenia.com).

The predominance of these and other factors probably varies from person to person in schizophrenia (Encyclopedia Britannica, 2008).

It is becoming more evident that having a gene or genes linked to schizophrenia is just the start. If you aren’t exposed to the environmental factors that contribute to schizophrenia, then it is likely you will never get it (schizophrenia.com).

Having a predisposition and being exposed to certain environmental factors certainly increases the chances of developing schizophrenia. The more environmental factors you are exposed to, the higher the risk (schizophrenia.com).

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Genetics - Chart

Experts now promote that schizophrenia along with all other mental illness is caused by a combination of biological, psychological and social factors, this understanding is called the bio-psycho-social model.

The following charts show the probable factors and path leading to the onset of schizophrenia: Chart taken from a presentation by Dr. Ira Glick, “New Schizophrenia Treatments” (as shown on schizophrenia.com).

Genetics - Chart

Chart taken from a presentation by Dr. Ira Glick, “New Schizophrenia Treatments” (as shown on schizophrenia.com).

Genetics – Family Studies

 Family risk studies:      Compares the observed frequency of the mental illness in close relatives of a patient vs. the frequency in the general population (Encyclopedia Britannica, 2008).

“First-degree relatives (parents, siblings, and children) share 50 percent of their genetic material with the patient, and higher rates of the illness in these relatives than expected indicate a possible genetic factor” (Encyclopedia Britannica, 2008).

Further information on the impact of genetics versus environmental factors can be taken from comparing identical twins reared together with those reared apart (Encyclopedia Britannica, 2008).

Adoption studies comparing children whose biological parents who had schizophrenia with those whose parents did not can also be useful in separating biological from environmental influences (Encyclopedia Britannica, 2008).

“These studies have demonstrated a clear role for genetic factors in the causation of schizophrenia” (Encyclopedia Britannica, 2008).

Genetics – Risk Chart

The Dopamine Hypothesis

 States that the excess of dopamine activity in the mesocortical dopamine system produces the positive symptoms of Schizophrenia.

 This was discovered by accident in 1950 by Henri Laborit when he noticed that antihistamine drugs prescribed to his patients reduced anxieties without producing mental confusion.

The Dopamine Hypothesis

  Chemist Paul Charpentier developed chlorpromazine (antihistamine) and tested it on animals which was later tested on humans.

It proved to be an effective treatment only for patients with schizophrenia by alleviating or eliminating their hallucinations and delusions.

How does this work you ask…

 Chlorpromine acts as a dopamine antagonist by blocking postsynapic dopaminergic receptors thus supporting the dopamine hypothesis.

  Other experiments show that chlorpromine and other antipsychotic drugs selectively bind to dopamine receptor sites.

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The Dopamine Hypothesis

People with schizophrenia have occasionally been found to have abnormally high levels of dopamine metabolites in their blood plasma.

In addition, drugs such as amphetamines and cocaine that increase dopamine activity in the CNS can often produce positive symptoms of schizophrenia in individuals without this disorder.

The Hypofrontality Theory

 States that the negative symptoms of schizophrenia are caused by decreased activity in the prefrontal cortex.

 In PET scans, it has shown that people with schizophrenia show decreased metabolic activity in the frontal region of the brain.

Support for this Hypothesis

 Damage to the prefrontal cortex in people who do not have schizophrenia often have motivational difficulties, confusion, decreased speech, flat affect, and social withdrawal.

 Also researchers have concluded that the negative symptoms of schizophrenia reflect prefrontal cortex deficits.

Problems with this Theory

 Not all persons with schizophrenia exhibit hypofrontality  Recently in a meta analysis involving more than 4000 people with schizophrenia, hypofrontality was exhibited in approximately half of the patients (Davidson & Heinrichs, 2003)

Abnormal Brain Structure

      Enlarged ventricles Smaller temporal and frontal lobes Smaller amounts of gray matter Abnormal blood flow Abnormal amounts of neurotrophins Disorganized hippocampal cells

Viral Infections and Schizophrenia

  Fetal exposure to viral infections such as influenza  Many individuals with schizophrenia are born in winter months Toxoplasma gondii  Intracellular parasite found in cat feces or uncooked meat   Known to cause abortions and stillbirths Can also cross the placenta and cause changes in head size,deafness, cerebral palsy, mental retardation and later in life- psychosis such as delusions and hallucinations

Sociocultural Views  According to Comer (2007), sociocultural theorists believe that people with mental disorders are victims of social forces. They say that both social labeling and family dysfunction contribute to the development of schizophrenia.

 Social Labeling: certain features of this disorder are influenced by the diagnosis itself (Modrow,1992 as cited in Comer, 2008). The label of schizophrenic is given to those persons in society that do not conform to certain norms or behaviors.  Regardless of whether the label is justified or not, it does become a self fulfilling prophecy, which then promotes the development of several schizophrenic symptoms.

 Being labeled “crazy” might encourage people to display psychotic behaviors (they accept and play the role). Dangers of diagnostic labeling (Rosenhan, 1973).

Family Dysfunction

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Theorists have said for years that certain patterns of family interaction can promote or sustain schizophrenic symptoms.

Schizophrenia has often been linked to family stress (Boye et al., 2002; Schiffman et al., 2002, 2001; Miklowitz et al., 1995 as cited in Comer, 2007). Parents with people who have schizophrenia more times than not 1) display more conflict, 2) have greater difficulty communicating with one another, 3) are more critical of and over-involved with their children than other parents. Family theorists have observed that some families are high in express emotion. This means that the family members criticize, disapprove of, are hostile towards each other as well as intrude on one another’s privacy very frequently . People who have this disorder and live with such families are four times more likely to relapse, while trying to recover (Comer, 2007).

Double Bind Hypothesis

   This is a theory that says that some parents communicate mutually contradictory messages to their children which places them in a double bind situation. This causes the children to constantly displease their parents “never doing anything right”.

Double-bind messages are primarily verbal and non-verbal (contradictory metacommunication) (Comer, 2007).

Children repeatedly exposed to this kind of communication will develop strategies to cope. Some children will ignore the primary communication and respond to the non-verbal communication, they become suspicious of what is being said to them (always trying to figure out the meaning behind what is said), focus on clues in gestures, tones. When one increasingly responds to messages in this way, then they may move towards becoming a paranoid schizophrenic (Comer, 2007).

Sociocultural-Existential View   This is a theory that was developed by a clinical theorist named R.D. Laing.

This theory combined sociocultural views with existential ones. It argues that schizophrenia is a constructive process where people try to cure themselves of the unhappiness and confusion caused by their social environment. Liang said that if these people were left alone then they would get better.

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References

In Depth Schizpophrenia Information and Support. Retrieved March 12, 2008, from www.schizophrenia.com

: http://www.schizophrenia.com/hypo.php

mental disorder. (2008). In mental disorder. (2008). In Encyclopædia Britannica.

March 9, 2008, from Encyclopædia Britannica Online: http://search.eb.com/eb/article-32322 Encyclopædia Britannica.

http://search.eb.com/eb/article-32320 Comer, R., J., (4th ed.). (2007). Retrieved Retrieved March 9, 2008, from Encyclopædia Britannica Online: Fundamentals of abnormal psychology. New Y ork: Worth Publishers.

Klein, S. B. & Thorne, B. M. (2007). Worth Publishers Biological psychology. New York, NY: Torrey, E. F., Yolken, R. H. (2003). Toxoplasma gondii and schiophrenia. Emerging Infectious Diseases, 9, 1375-1380.