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Ask the Mental Health Expert Archives 2001-2004

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Hereditary Schizophrenia

Q. Hi, I am a 19-year-old male and my mother has paranoid schizophrenia. I also have two older brothers that have been diagnosed with some type of schizophrenia. I was wondering what are my chances of getting this disorder. I have noticed at times I do seem to get paranoid. I get nervous around people. Sometimes I get anxiety and other times I will feel down and depressed. Although they are not very severe feelings, I still wonder if they will get worse. What should I do about these feelings and do you think I should see someone to get checked out? Thanks for your time.

A. These are good and important questions to be raising at this time in your life, even if they have no easy answers. First, while I can't give you a precise percentage risk for your developing schizophrenia--after all, it's not clear precisely what the diagnosis is for your siblings--I can give you some background information.

What we know about schizophrenia is this: there is a strong genetic input, but genes aren't the whole story. If they were, we would know that if one identical twin develops schizophrenia, the other one would do so, too, with 100% certainty--just like blue eyes or blond hair. But we know that schizophrenia doesn't work that way--that is, even with identical twins, the concordance rate"(chances of both twins having schizophrenia) is not 100%. Why not? Most likely, there are non-genetic variables that affect the outcome, including perinatal factors (maybe which twin was exposed to greater blood flow in the uterus, or perhaps viral factors, etc.) and social-environmental factors that arise later in life.

So, what's written in our DNA is not written in stone. That said, some data show that the children of mothers with schizophrenia have a significantly higher frequency of schizophrenia than do the offspring of normal mothers--about 9% versus 1% (Tienari, 1991). Similarly, the concordance rate in non-identical twins is about 8-12%, versus 1% in the general population. The concordance rate for identical twins is about 50%. So, while the genetic deck may be stacked in favor of schizophrenia for some people, nobody is fated to develop the disease.

There is also some very preliminary evidence--not supported in all studies--that early intervention may help reduce the severity of schizophrenia later on. As far as your occasional paranoid feelings and nervousness around people--these need not be signs of schizophrenia, but only a thorough evaluation by a mental health professional could clarify that. Sometimes, simple anxiety can explain these feelings. And so, yes, I would advise you to see a psychologist or psychiatrist about your depressed and anxious feelings. There are forms of psychotherapy, as well as medications, that can be very helpful for these problems. I wish you well, and urge you to see your life as an open book--not one already written!

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August 2001

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