Is Schizophrenia Inherited?
Schizophrenia is one of the most serious and disabling mental illnesses. It is
associated with disturbances in the way an individual thinks, perceives, feels,
and relates to others. Genes and environment both contribute to its development.
No specific genes have yet been identified that lead to the development of
schizophrenia, but a number of gene regions on a few chromosomes have. When
neither parent, and no close relatives, have the condition, risk is about one
percent; when one parent has the disorder, 13 percent; when both parents have
the disorder, 46 percent. However, genes themselves do not guarantee development
of the disorder. Nearly 90 percent of people with schizophrenia have neither
parent who is affected; a sizable majority (63 percent) have no affected first-
or second-degree relatives.
Studies have shown that adopted children born to a parent with schizophrenia do
develop schizophrenia as adults at rates considerably higher than the
one-percent rate in the general population.
No specific environmental influence by itself has been identified as a
significant risk factor, but some "toxic" factors would include demoralizing or
threatening physical environments, emotionally demanding experiences, emotional
understimulation, and chronic disruptions to attention or information
processing.