Risk factors and Schizophrenia

Okay so last week I talked a little bit about the need for good quality research into mental health problems and it occurred to me that I haven’t really looked at any scientific research about the causes or risks of getting mental health conditions. I’ve really focussed on the ramifications of having them and living with them so this week I thought I’d look into that.

You may or may not think that I have a healthy distain of all things reported in the newspapers and you may think that this has extended to scientific studies to. Well I can’t honestly say that you’d be wrong however I do hope that I haven’t made you think that I am anti authority, anti science, anti media. I feel that I have healthy inquiring mind and that although this has often led me to be rather critical of some studies I do think it has helped gain some perspective on what is and is not being reported and so when I look at articles I do consider other alternatives to the conclusions the writers have drawn and I would encourage you to do the same.

It is often said that all people have ‘an agenda’ and to some extent this is true particularly of people who write journal articles or parts of the media but what is written is only part of what is there and other explanations are possible. I feel it is important to remember this because at present so very little research has been done into the causes of mental health conditions and therefore there are relatively more assumptions being made than in other areas of science.

I’m probably trying to teach granny to suck eggs but it seems that so many people have lost sight of this. If you read the comments left at on line services for newspapers it becomes apparent that people are believing what is written are the only conclusions to be drawn from any set of data and are outraged over things that when the data is looked at more closely, can be explained differently.

So to risk factors for schizophrenia

I’ve chosen this disorder simply because recently I have seen quite a few articles written about it. Sadly many of them are of rehashed datasets and not de novo studies however reviews are helpful.

Much is known about this disorder and information can be found at Wikipedia, on NHS sites and many other places should you wish to trawl through them but what I’m going to look at are the bits that interest me and a couple of articles I found recently.

One article I found entitled

Smoking Seen as Schizophrenia Risk Factor

Might appear at first glance to be suggesting that smoking puts you at risk of becoming Schizophrenic however if you read the article properly you see that actually that the risk is in the affect that smoking can have on a particular group of people with the TCF4 gene and not everyone in general.

“Smoking alters the impact of the TCF4 gene on acoustic stimulus filtering,” said Quednow, explaining this kind of gene-environment interaction. “Therefore, smoking might also increase the impact of particular genes on the risk of schizophrenia.”

However one thing they don’t suggest is that reducing the number of cigarettes a sufferer smokes may reduce problematic symptoms, which seems odd to me.

This article aside I am more interested in the environmental factors, than the genetic ones that may lead to someone suffering this disorder. In many ways I feel that people focus too frequently on the genetic ones and possibly this is because of the misunderstanding of the term heritability and the big question will my child get schizophrenia if I have it?

 The media quotes so many different levels of heritability and many assume that this means genetic inheritance but it doesn’t and as I’m not good at explaining the concept I found someone who can. Please read this fully as it takes a bit of getting through but really does get to grips with the difference.

 Schizophrenia is (arguably*) 80% heritable; it is not 80% genetic http://mancpsychsoc.blogspot.co.uk/2011/10/schizophrenia-is-arguably-80-heritable.html

So to the environmental factors So what are they?

Basically they everything else that is not attributed to control by your genetic code, however they can, as with smoking, affect how your genetic code is interpreted and therefore works thus two individuals with identical genetic code may not both become ill with schizophrenia. So if you look at this site http://www.schizophrenia.com/research/hereditygen.htm they say;

It is of much interest, though, that the correlation of schizophrenia between identical twins, who have identical genomes, is less than one-half. This indicates that schizophrenia is NOT entirely a genetic disease

They go on to say

Research also increasingly suggests that - like diabetes - many cases of schizophrenia may be preventable

Which is good news however that does not necessarily mean that you can. At this stage it is important to consider what factors influence the occurrence of schizophrenia and this paper in the Lancent (from 2009) goes into some detail about the disorder. http://xa.yimg.com/kq/groups/19525360/611943554/name/Schizophrenia+-+The+Lancet.pdf

Factors that may affect the occurrence

·         Perinatal, hypoxia, maternal infection, maternal stress, maternal malnutrition, maternal use of drugs

·         Living in an urbanised area, living in non ethnic environment (migrants) or with few individuals of the same ethnicity

·         Use of cannabis

·         Exposure to trauma during childhood

As you can see some of these things are not particularly controllable and others more so. For instance good nutrition during pregnancy and not using drugs are quite easy. Where you live not so much.

When it comes to exposure to trauma during childhood you may assume that actually this would be uncontrollable to an extent however the kind of trauma that this article may be referring could be.

I found this article Childhood Adversities Increase the Risk of Psychosis: A Meta-analysis of Patient-Control, Prospective- and Cross-sectional Cohort Studies http://schizophreniabulletin.oxfordjournals.org/content/early/2012/03/28/schbul.sbs050.full.pdf

A big title that looks into this very thing. In this article they define adversities as

·         childhood sexual abuse (sexual acts toward a child, including intercourse, touching,etc.)

·         childhood physical abuse (violent acts leading to physical injury or harm, such as harsh physical punishment)

·         childhood emotional abuse (exposure to behaviour that might result in trauma, such as harshness, name calling by parents during childhood),

·         childhood physical neglect (failure of those who are responsible for physical care to provide this care during childhood, eg, by failing to provide food or clothes),

·         childhood emotional neglect (failure of those who are responsible to provide emotional care to provide this care during childhood, eg, by being unresponsive to a child’s emotional needs),

·         bullying (an act of repetitively aggressive behaviour by a peer with the intention to hurt the child, such as physical assault or intimidation or repeated name calling).

All things that I feel most people would agree should be reduced as far as possible for every child.

So the question then becomes how much of an influence on the occurrence of schizophrenia do these things have. Well this paper boldly announces that all things being equal by removing these traumas from the patients’ lives they could reduce the rate of psychosis by 33%. Now there are a lot of caveats to this but what it’s saying boils down to this.

The emotional and physical environment in which the child is brought up in could account for not a large number but a significant amount of the reason for psychosis.

Now psychosis isn’t schizophrenia and whether a child goes on to develop schizophrenia was not part of the study but they did have this to say in the discussion.

Our findings suggest that clinicians should routinely inquire about adverse events in childhood in order to develop comprehensive formulations and treatment plans when working with patients with schizophrenia or similar diagnoses

And although they don’t say that it could be part of the reason they are certainly suggesting that it helps reduce the symptoms of the disorder which in turn could suggest that it be part of the reason.

They also suggest that other traumas such as

medical illness, exposure to war, natural disasters, parental separation

could also have adverse affects that increase the risk as well. It seems clear to me that trauma whether emotional or physical or both has a detrimental effect that goes far deeper than most people estimate and as such it might be prudent for us all spend more time considering how we feel about such events. And certainly given the current trend of working mothers/ divorce rates and single parent families more research really needs to be done quickly.