How Hereditary Is Mental Illness?

Some persons have a predisposition toward mental illness. They are not very well equipped at birth to cope with these stresses. It is like persons who are born financially poor compared with others who are born rich. Certainly. those born poor are far more likely to run into debt, or land on the welfare rolls, than those born rich. Similarly, due to heredity some are born "poor" emotionally and so are more likely to run into "debt" psychologically, and suffer some form of mental illness.

Supporting this illustration and conclusion are the words of Dr. David Rosenthal: "In most cases, an inherited factor needs to be present for schizophrenia to develop. However, without severe environmental stresses the illness may not appear in those who have a predisposition to it."

Research has disclosed that the closer one's blood relationship to a schizophrenic, the greater the likelihood that one will also become a victim. Thus if one parent is afflicted, there is one chance out of six that a child will be also. If both parents are, the chances are four chances out of six.

That schizophrenia might have such a physical source was demonstrated by a group of psychiatrists who injected blood from schizophrenics into two normal prison volunteers. Soon after the injection, one lapsed into a stupor-like state and had hallucinations. The other became paranoid; he suspected everyone was talking about him. After about two hours both became normal again.