PET scans can not prove that an increased level of dopamine activity can cause schizophrenia.
It is likely that most of the drugs prescribed act to block dopamine receptors in the brain. They are usually effective in treating the acute symptoms and prevent relapses and all schizophrenics should be on such medication. Side effects are common and depending of the seriousness of this effects medication has to be stopped or changed.
The chronic symptoms are treated at the present time with clozapine ( Clozaril) and risperidone ( Risperdal ).Neuroscientists believe that the seeds of the disorder lie during the foetal development. Shore believes differences of the brain occur during fetal development.
Weinberger agrees but does not see it as the entire reason for the disorder but one of them. Based on the evidence of their research, half or more of schizophrenics seem to have abnormalities in fetal brain development. When the brain is first taking shape, the subplate in the brain guides the cells to their destined places, but certain cells are placed to areas where they not belong to and leaving other areas totally out. This leads to faulty connections, and that is what they found in the brains of schizophrenics.
Evidence for that theory comes from autopsies of patients brains were neurons out of place in the prefrontal areas of 7 of 20 patients with schizophrenia and not one of the 20 brains from people without the disorder.Once the child is born the subplate disappears shortly afterwards and the damage done is irreplaceable. It does not explain while symptoms of schizophrenia do not appear for almost 20 years and more. But some researchers in a 1994 study asked families of schizophrenic patients for home movies when their son or daughter was at the age of 2 and found out that these children would display odd movements with their hands. Parents easily ignore this but for the researchers first signs of the disorder. Some speculation is that brain connections might misdevelop when the mother catches a virus during early pregnancy.In 1957 in Helsinki, Finland, first evidence of this theory came from a study of children born after a flu epidemic.
Mednick found that mothers who had flu in the second trimester of pregnancy, they had a greater chance of developing schizophrenia as adults. The 2nd trimester is seen as one when the subplate goes into action to develop the brain. Another study supports this theory. Higher rates of schizophrenics are born among children born in the month of December to March, a time where exposure to flu or other viruses is more common. Some believe it might be because of malnutrition.
In 1944-45, when Nazis blockaded Dutch cities, they found a higher rate of children developing schizophrenia.Relapses of schizophrenia are more likely to happen in emotionally charged surroundings. These measurements of these have been surroundings are called expressed emotion (EE). Most of the relapses happen in family surroundings but this does not mean that it causes schizophrenia. It is argued that families can reduce critical and sarcastic comments, rising of voice, arguing hostility, over-involvement and over-concern, to mention a few items on the EE scale the relapse rate would go down and fewer would go back to hospital.Vaughn and Leff (1976) found a 51% relapse in high EE homes compared to only 13% in lower EE homes.
Earlier Brown (1972) examined EE. He also found that with high EE homes, discharged patients had a much higher rate of relapse when the face to face contact increased. This theory is still accepted today. Relapses can also occur at events such as loss of a relative or friend and loss of job.
Fromm-Reichmann in 1948 described families with high emotional tension as schizophrenogenic. Signs of this are close alliances, many secrets and conspiracies. Relating to this theory Bateson (1956) believed that parents are to blame. His suggestion was that parents expressed care on the one hand but criticised their children on the other. He argued that they are overprotective and rejecting, too involved, too restrictive and too permissive.
This leads to confusion, self-doubt and finally withdrawal. He named this the double-bind theory.In the 1960s R.D.Laing saw schizophrenia as people behaving in a different way. He argued that doctors had no right to interfere.
At this time, schizophrenia was seen as a result of abnormal relationships or disjunction within the family. Laing’s views caused terrible consequences as families blamed themselves, feeling guilty about what had happened to their children. Schizophrenics did not receive any treatment because of this view and research was not slowed down. Even there was no evidence for this view; it was not possible to prove it wrong.
Another environmental study by Tienari (1987) found that all families with schizophrenic patients seemed to be disturbed. Both parents often try to dominate and devalue the other one in the relationship. Schizophrenia was also found to be below average at families rated as healthy.There is little doubt that schizophrenia has a genetic component but opinions on the extent of this seem to differ. If genetics alone are responsible, then an identical twin from the same egg should both have the disorder and the concordance rate would be 100%. But this is not the case.
Looking at the social and environmental theories there are plenty of disturbed families but only a few develop schizophrenia. Also diets, foetal development and viruses could play a role but on their own there is no prove. All in all there is a strong belief that schizophrenia has several causes which scientists are desperately searching to find to prevent and cure the disorder to help those who are effected and their relatives.Harrison, P Schizophrenia- A misunderstood disease- Psychology Review, November 1995Psychopathology – Atypical Development and Abnormal Behaviour P.246-254Rose, S; Lewontin, R.
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