Schizophrenia — Are genes involved?
Originally Published: May 16, 2003
My father has schizophrenia. My great grandmother was manic-depressive. What are the genetic risks of my child being schizophrenic if I have one? Are there any tests that can be done either before becoming pregnant or prenatally to determine probability? Has a gene been found linked to schizophrenia?
Before getting into the specifics of genetic and other risk factors for schizophrenia, the distinction between schizophrenia and manic-depressive disorder, since you mention both, needs to be clear. Schizophrenia is a psychotic disorder, which is a group of mental illnesses marked by hallucinations and other psychotic symptoms; whereas manic-depressive disorder, similar to depression, is a mood disorder. For more information on manic-depressive disorder, see Manic-depression? in Alice's Emotional Health archive.
Schizophrenia is often talked about, but commonly misunderstood. Its symptoms most often include hallucinations, delusions, paranoid thoughts, and hearing inner voices that no one else can hear. People with schizophrenia also have a distorted sense of reality and a loss of the ability to express emotions. Because the symptoms are so severe, a person with this illness often becomes fearful, withdrawn, and can become so disorganized in speech and action that s/he doesn't make sense to others. Those who are close to someone with schizophrenia can also become frightened by that person's confused and disoriented behavior.
Some people with schizophrenia have episodes of the above-described symptoms, but lead mostly normal lives during the intervals between those episodes, especially with the help of antipsychotic medication. Others have chronic schizophrenia and require long-term treatment. Schizophrenia affects about 1 percent of the population universally throughout the world, and males and females are equally likely to have it. The disease usually appears earlier in men late teens to twenties than in women late twenties to thirties.
Schizophrenia usually requires treatment with antipsychotic medications that can subdue the frightening symptoms of the disease and allow the person to lead a relatively normal life. In conjunction, most persons with schizophrenia benefit from psychosocial therapy, which focuses in a number of different ways on allowing them to function normally, ranging from individual psychotherapy for the patient to educating a schizophrenic's family about the disease. Schizophrenia can be treated, and it's important that anyone experiencing symptoms that sound similar to schizophrenia sees a health care provider as soon as possible.
In popular imagination, schizophrenia is often linked with both violence and split personalities. Neither prejudice is true. Personality disorders are an entirely different subset of mental health diseases. And contrary to being violent, people with schizophrenia mostly want to be left alone. The only aspect of violence to which those with the illness are prone is towards themselves: suicide. Approximately ten percent of schizophrenics kill themselves.
To answer your more immediate question surrounding the causes of schizophrenia, and particularly your family's history: there does appear to be evidence that genetics play some role in causing the disease. At the same time, research underlines the importance of environmental factors. Similar to almost any other illness that has more recently been linked to our genes, familial background is only one factor out of many.
Children of people with schizophrenia have about a 10 percent chance of getting the disease themselves. That's ten times greater than the general population's risk. Second-degree relatives (your child) have a risk of about twice that of the general population. It is currently not known which gene or genes might be responsible for this increased probability, so there are no tests that can help determine any individual's actual risk for developing schizophrenia.
Genetic probability is not fate. A host of other factors may or may not contribute to a person's becoming schizophrenic, including environmental and behavioral factors. The causes of schizophrenia are not yet well understood by scientists.
Your child, if you have one, would only have a 2 percent chance of developing the disease; not that much of an increase from the 1 percent chance that s/he would have were s/he born to anyone without a schizophrenic parent. The slightly increased risk need not unduly affect any decisions you make about your having children in the future, but you may want to explore your concerns with a psychotherapist. If you would like to speak with a genetics counselor, a referral can be found through the March of Dimes web site.