Genetics and Parental Origin As Risk Factors for Schizophrenia

Schizophrenia is a mental health condition that can severely impair an individual’s quality of life. People who are at risk for schizophrenia sometimes exhibit early symptoms, such as psychosis or hallucinations. However, other risk factors exist that increase a person’s chance of developing schizophrenia. In Denmark, studies have been conducted that show that second-generation immigrants are more likely to develop the illness than nonimmigrants. Although discrimination could play a role in risk, more needs to be known. As a follow-up to previous research, Carsten Bocker Pedersen of the National Centre for Register-based Research at Aarhus University in Denmark recently led a study that explored the relationship between risk and parental origin or genetics with regards to schizophrenia.

For his most recent study, Pedersen compared 892 individuals with schizophrenia to 883 control subjects and assessed their genetic history as well as their parental origin. He found that the participants who were born to foreign-origin parents were almost twice as likely to develop schizophrenia as those born to Danish citizens. Additionally, individuals with genetic variation were two and half times more likely to develop the illness than those with no genetic variance. Pedersen based his research on data collected from the Danish civil registry and examined the alleles of the participants to determine the genetic variance.

Although there are many other risk factors for schizophrenia, this research sheds some new light on two factors that may increase a person’s vulnerability. Therapists and mental health professionals working with people at risk may want to look at both of these factors independently and together, when assessing the likelihood of schizophrenia. Pedersen added, “In terms of relative risk of schizophrenia, genetic divergence and parental foreign country of birth are interchangeable entities and both entities have validity with regard to identifying second-generation immigrants.” Because this research was conducted with Danish citizens, future studies should focus on other ethnic groups to determine if this finding extends across cultures.

Pedersen, C. B., Demontis, D., Pedersen, M. S., Agerbo, E., Mortensen, P. B. (2012). Risk of schizophrenia in relation to parental origin and genome-wide divergence. Psychological Medicine 42.7, 1515-1521.

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  • ZOE


    June 12th, 2012 at 3:32 PM

    I would like to see this same sort of study conducted in other countries to see if the same thing holds true. I just can’t help but feel like discrimination does not play a role in developing schizophrenia since that is an external factor that would seem to have little bearing on brain development. I would like to know if there are other countries that experience the same sorts of numbers of their immigrants, and then how those same people would fare in Denmark. I know, its reaching, but in order to have the most validity you know that there has to be more indepth and continuing study into this issue.

  • Stevie


    June 12th, 2012 at 5:16 PM

    Genetics and parental origin?Hmm, seems like many other disorders which are known to be more prevalent in one part of the world.

  • flay


    June 12th, 2012 at 5:58 PM

    maybe the Danes just have a lower rate of schizophrenia as a whole?

  • Collins R

    Collins R

    June 13th, 2012 at 4:17 AM

    I do believe that part about genetics playing a large role in whether you have schizophrenia or not. But where your parents are from? Seems a little like that is reaching for an something that is not the real answer.
    But let’s suppose for a minute that it is: would the realization that this in fact causes this to form in certain people, will that be enough to keep others in the majority group from discriminating unfairly against these groups of people?

  • Charlotte LeBlanc

    Charlotte LeBlanc

    June 13th, 2012 at 6:52 PM

    Genetics certainly play a role in any weakness or in some illnesses in the body.

    “In the latest issue of Biological Psychiatry, researchers at the University of California in San Diego suggest that careful analyses of the electrical signals of brain activity, measured using electroencephalography (EEG), may reveal important harmonic relationships in the electrical activity of brain circuits. The underlying premise is a simple one – that brain function is expressed by circuits that fire, and therefore generate oscillating EEG signals, at different frequencies.

    As circuits interact with each other, one would see different “musical combinations”, like the chords of music, emerging in the EEG signal. Abnormalities in the structure and function of brain circuits would be reflected in cacophonous music, chords where the musical “voices” are firing at the wrong rate (pitch), volume (amplitude), or timing.”

    Dr. John Krystal, Editor of Biological Psychiatry, commented, “The new findings highlight the importance of understanding the relationships between different circuits. It seems that cortical abnormalities in schizophrenia disturb brain function, in part, by disturbing the ‘tuning’ of brain circuits in relation to each other.”

    This makes sense to me. My son suffered with this dreadful illness for 8 years and is now leading a normal, med-free life.

  • Blake Griggs

    Blake Griggs

    June 14th, 2012 at 5:52 AM

    I am a little confused, okay a lot confused, because I would have never guessed that whether someone is born to foreign parents would have any kind of sway over whether or not they become a schizophrenic. Now I know that your genetics are going to play a large role, and that there are certain cultural groups who are more susceptible to certain genetic diseases. I suppose that the same could be true with mental illnesses as well as physical illnesses. I had never really given much thought to this though, so for that, as usual I would like to thank the contributors of this site for opening my eyes to the possibilities that could be.

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