[teejai]

http://psychminded.co.uk/news/news20...phrenia005.htm

"Unlikely" that key genes cause schizophrenia

EXCLUSIVE
by Adam James

April 14, 2008

.....

The genes most widely believed to cause schizophrenia are, in fact, unlikely to play a role in the condition, according to the most comprehensive genetic study of its kind.

The results published in a paper in this month’s American Journal of Psychiatry will re-ignite the so-called "nature/nurture" debate in schizophrenia, which one in 100 people are diagnosed with.

America-based clinical psychologist Dr Jay Joseph and author of The Missing Gene: Psychiatry, Heredity, and the Fruitless Search for Genes said: “The reason that this latest study did not find evidence for a gene is that there are no such genes. For 25 years psychiatry has been looking for a schizophrenia gene. They keep failing."

A total of 23 researchers from America, Australia and France examined a total of 14 “candidate genes” that, until now, scientists have claimed to be most linked to schizophrenia.

The study is significant because it is based on the genetic material of 1,870 unrelated patients diagnosed with schizophrenia or schizoaffective disorder, and 2002 control patients. This made it the largest ever sample in a study examining the genetics of schizophrenia.

The study tested the hypothesis that a type of DNA difference called single nucleotide polymorphisms (SNPs) in the 14 genes has a role in causing schizophrenia.

In total, 433 SNPs in these genes were examined in a bid to “tag” the DNA variation linked to schizophrenia among people of European descent.

"We did not detect a significant association of schizophrenia with SNPs in 14 candidate genes that have been of great interest to the field,” wrote the authors.

"Our results suggest that, taken together, common DNA variants in these 14 genes are unlikely to explain a large proportion of the genetic risk for schizophrenia in populations of European ancestry.”

It is the “most comprehensive” study yet into a genetic link to schizophrenia, wrote Dr Steven Hamilton of the Department of Psychiatry and Institute for Human Genetics at the University of California in an editorial in the journal.

The study’s lead researcher Professor Pablo Gejman, director of the Centre For Psychiatric Genetics at Northwestern University in Illinois, admitted the results were not "as expected”.

"The genetics of schizophrenia has remained illusive at a molecular level for more than 20 years,” he said.

Psychiatry has argued for a genetic basis for schizophrenia since the 1970s when studies on same-egg twins who were separated at birth and were both diagnosed with schizophrenia.

But some scientists argue the twin studies could equally support the hypothesis that a person's upbringing causes schizophrenia, as the twins shared the same background.

They also highlight that modern molecular research has consistently failed to locate genetic markers for schizophrenia.

Mary Boyle, emeritus professor of clinical psychology at the University of East London, said: “Research has never shown any link between genes and schizophrenia. There has been a vast amount of time and money spent. Yet nothing has come from it. If this was any other area of research serious questions would have been asked.

"If people want to continue this research good luck to them. But my worry is that they are being given public funding.”

Dr Joseph said: "Many people have dedicated their life to the genetics of schizophrenia. And they are not going to now turn around and they have been wrong. It is up to a young generation of researchers to introduce a new scientific paradigm.”

Nick Craddock, professor of psychiatry at Cardiff University and a leading UK geneticist said, however, that it can not be concluded from this study that genes are not involved in the aetiology of schizophrenia.

"This study does not mean none of these genes might be involved,” he said.

"There maybe different variants of these genes. And it certainly does not mean that genes are not involved in schizophrenia. It does mean that these particular 14 genes do not seem to have a major role in the sample used in this study."

Professor Craddock agreed with the journal study’s authors who suggested more “robust” findings on a genetic cause for schizophrenia could come from examining variants on a multitude of genes, called genome-wide association methods.

"There is now a move towards studies looking at half a million different gene variants. This is the way to go,” said Professor Craddock.

The 14 genes investigated in the American Journal of Psychiatry paper, entitled No Significant Association of 14 Candidate Genes With Schizophrenia in a Large European Ancestry Sample: Implications for Psychiatric Genetics were RGS4, DISC1, DTNBP1, STX7, TAAR6, PPP3CC, NRG1, DRD2, HTR2A, DAOA, AKT1, CHRNA7, COMT, and ARVCF.

[pachyderm]

Heh, heh! What else is new?

Genes + environment explain everything...

(No, I don't mean to put down teejai.)

[teejai]

</font><blockquote><div id="quote"><font class="small">Quote:</font>
pachyderm said:
Heh, heh! What else is new?

Genes + environment explain everything...

(No, I don't mean to put down teejai.)

</div></font></blockquote><font class="post">

There's attempting to put me down and there's actually succeeding


There seems to be arguments for and against genetics re schizophrenia with both sides seeming to have 'political' reasons for supporting the line they do.
Many psychologists seem anti the genetic angle whilst psychiatrists are predominantly pro the genetic angle.

I think the best one can say is that the jury is out. Certainly twin studies point to some genetic contribution but if 'genetic contribution' was a prisoner in the dock he would perhaps have to be found innocent re 'beyond reasonable doubt' as the evidence stands .That is not to say those supporting the genetics argument
are necessarily wrong but if right have not proved their case sufficiently for the 'prisoner in the dock' to be convicted as things stand

In the spirit of fairness i post things pro and anti the genetic connection as and when i find them, with my own personal belief leading me to believe that there is some genetics involved but not as much as the pro genetic camp argue.

Either way this one is going to divide opinion for some time to come until a definitive case can be made either way .

[pachyderm]

> twin studies point to some genetic contribution...

Of course there is a genetic contribution! I'd say that there is a genetic contribution to just about any disease. We are all somewhat different. But most of the stories (or headlines) saying things like "key genes cause schizophrenia" imply that they are the only things that really matter. For someone who has symptoms similar to those of schizophrenia, and who is pretty sure there is an environmental contribution to their origins, I often find these stories triggering -- particularly because the treatment one gets under these theories denies the reality of the history that the person knows to have happened. One is told that "what happened to you did not happen to you" or at least, it is of no significance...

[embarassed]

I agree. Genes contribute to mental illnesses but they are not the sole cause. I have a problem with people who deny the importance of social environmental and life events. It's like they're dismissing the crap I went through. It's hurtful and invalidating. I think people sometimes overemphasize genetics because it is a convenient way to escape responsibility. It's easier to blame an illness completely on a person's brain than to admit that someone might have done something to the person.

[PsyChris]

This is the third time there has been a major negative study for a genetic basis of Schizophrenia. The first occurred when almost 100% of the population with Schizophrenia were committed to State Mental Hospitals. There was relatively no reproduction among Schizophrenic people...yet the disease persisted at the same rate, if not higher in the US

When the study with the twins came out they seem to have forgot the prior study. They thought once the human genome has been de-coded we could find the Schizophrenia gene! Well, that didn't work either.

So instead of looking for a specific gene, they though they would look for a mutated gene that would lead to Schizophrenia. If you wanted to describe the first method it's like looking for the Toyota in a row of Fords. The second method is like looking for the red Ford in a row of blue fords.

This is the nature of science though. I really don't want them to stop looking for a genetic cause but this does put a damper on things.

There are many other theories of Schizophrenia. I'm not sure where I stand on most of them.