Schizophrenia causes - Prenatal Environment

When we think of a child's "environment," we tend to think of their family and friends. In fact, our first "environment" is inside the womb. The nine months during which a baby develops inside the mother lay important groundwork for healthy development after birth. Researchers have found that there are qualities of the prenatal environment that may increase the likelihood that someone will develop schizophrenia. For example, research has shown that patients with schizophrenia are much more likely to be born following a complicated pregnancy or delivery. Additionally, schizophrenia patients are more likely to be born during winter months. There are two ways in which the prenatal environment may affect an infant with a genetic propensity for schizophrenia.

In 1957, there was an influenza epidemic in Helsinki, Finland. Sarnoff Mednick at the University of Southern California wanted to know if mothers who had the flu while they were pregnant were more likely to have children who later developed schizophrenia. Indeed, Mednick found that children who were born to mothers who had the flu in the second trimester were more likely to have schizophrenia as adults. Although researchers are still uncertain as to how exactly the influenza virus affects the unborn child, one hypothesis is that maternal antibodies cross the placental barrier and disrupt brain development.

Children whose mothers are malnourished may also be more likely to develop schizophrenia as adults. The Dutch Hunger Winter was a period of extreme famine in the Netherlands. In 1944, a Nazi blockade prevented many Dutch citizens from getting enough food for their families. Many people became very sick and some died from starvation. Research has shown that the children who were conceived at the height of the famine were twice as likely to develop schizophrenia as children who were conceived at other times. Fetal malnutrition may play a role in the development of schizophrenia.

What Causes Schizophrenia?

Schizophrenia is a complex illness, and no single cause has been found. There are several theories about the causes, which include:

• Heredity. Schizophrenia runs in some families. A person can inherit a tendency to develop the illness, especially if a parent has the disorder. The risk for inheriting schizophrenia is 10 percent in those who have an immediate family member with the illness, and 40 percent if the illness affect both parents or an identical twin. However, about 60 percent of people with schizophrenia have no close relatives with the illness
• Brain chemistry. Many researchers believe that people with schizophrenia are either very sensitive to a brain chemical called dopamine, or produce too much of it. Dopamine is a neurotransmitter, which are substances that allow nerve cells in the brain to send messages to each other. An imbalance of this chemical can affect the way a person's brain reacts to stimuli.