Journalist and mental health service user Richard Shrubb on how a family history of schizophrenia made him investigate the condition
Schizophrenia runs in my family, on my father's side. Two of my great-uncles had it. Though there are no cases in my father's generation, I am one of three people in my generation of the family to have the condition.
We have no evidence going further back of a family history of schizophrenia. My father says: "My uncles were young at the turn of the 20th century, and psychiatry itself was very young at that stage, so we can't be certain of previous generations before that."
The family history has caused me to investigate to what extent there is a genetic component to schizophrenia.
Element of heritability
Dr Anirban Dutt, clinical lecturer and grade research worker at the Institute of Psychiatry in London, says that, although there is an element of heritability, the causes of schizophrenia are complex.
He says: "What has been found cannot be of the certitude of something like Down's syndrome. Down's syndrome is an easy-to-spot disorder with definite characteristics. It can be expressed through a chromosomal abnormality. Schizophrenia is far more complex."
Last year, the international science journal Nature published a paper that discussed the results of three linked studies into the genetics of schizophrenia.
All three compared sequences of genes in people with schizophrenia and those without. A summary of the findings, by the NHS Knowledge Service, says they point to an association between schizophrenia and a number of different gene sequences on chromosome 6 in the "major histocompatibility region".
The "major histocompatibility region" is one of the most gene-dense regions of the human genome and many of the genes play a large part in the immune system. Simply, the studies have found a site on the human genome for further study, though they say that other sites may be involved. We are far from a blood test to show a predisposition for schizophrenia.
The genetics issue contributes to the debate on the differences between individual diagnoses of schizophrenia because two people can have totally different symptoms.
Range of genes
With the range of combinations of genes that may be required to create the disorder, are there indeed a number of sub-disorders which may even be separate in their own right? I for one have only heard voices during LSD "flashbacks" and have not hallucinated in this way for many years. I have a "paranoid delusion" which is considered to be "schizophreniform" in description.
Surely I have a different illness from someone who hears voices all the time. It may even lead to the term "schizophrenia" being treated the same way as cancer is now - yes, you have cancer, but what form? An aggressive skin cancer or a benign brain tumour?
Research points to schizophrenia being of "multifactorial causation" - it is caused by a range of events working in concert.
In the lead-up to my illness developing, I, like many other sufferers, smoked cannabis.
No one told me of the predisposition as I was the second in my generation of the three to have it and, until I had it, we could not be certain of any predisposition.
If I had known what I do now in my formative years, perhaps I would have made better life choices and not suffered a drugs-addled and high-stress collapse into mental breakdown.
Combination of factors
It seems that a combination in my case of genetics, prolonged stress and cannabis may have reached the critical mass responsible for the disorder developing.
Epigenetics - the study of the relationship between genes and the environment - is a relatively new branch of science. It could help explain why only three people in my generation developed the disorder despite all of us on my father's side having an apparent genetic predisposition.
Perhaps in future generations, where somebody has been determined as genetically predisposed, care would be taken in their upbringing to avoid the triggers that make the genes that contribute to schizophrenia start working.
There may be room for social care workers to change the outcomes of a predisposed child in future by encouraging a deliberately nurturing and comfortable upbringing.
My wife and I married in part because we don't want children - in my case, because schizophrenia is too terrible to risk passing on to future generations. The state of knowledge is still far too young and generalised for me to change this position - and may yet be for many years.
More on studies published in Nature