This is the VOA Special English Health Report.

People who are schizophrenic sometimes hear voices or see things that are not real. They might believe other people want to hurt them. They can become fearful and socially withdrawn.

Schizophrenia is explained on the National Institute of Mental Health Web site as a brain disorder that is severe and disabling. It is also chronic, meaning long term.

The disorder usually appears in males in their late teens or early twenties and in females in their twenties or thirties. Experts say it rarely appears in children, but when it does, it generally affects them more severely than adults.

Children with schizophrenia are often treated with "second-generation" antipsychotic drugs. But do these costly newer drugs work better than older ones that cost less? The National Institute of Mental Health recently paid for a study by four universities in the United States. The research teams found that the answer was no.

They studied one hundred nineteen people between the ages of eight and nineteen. The patients were observed over an eight-week period. Some received risperidone or olanzapine, two newer drugs. Others received a first-generation antipsychotic drug, molindone.

The researchers found that all of the patients experienced about the same improvement. But the risperidone and olanzapine caused serious weight gain.

In fact, the institute cancelled the olanzapine research because the patients who took it gained an average of almost six kilograms. The concern was that the weight gain could lead to diabetes.

The study appeared in the American Journal of Psychiatry.

Past studies have shown that children born to older fathers have a higher risk of schizophrenia as well as autism. Now, scientists are finding evidence of a similar link for bipolar disorder. This disorder is marked by periods of extremes in mood and behavior. It was formerly called manic depression.

A new study in Sweden involved more than thirteen thousand patients with bipolar disorder. Researchers compared them to similar people of the same age and sex who did not have the disorder.

The study found that fathers fifty-five and older were one and a third times more likely to have a bipolar child than fathers twenty to twenty-four. The scientists say the reason could be that older sperm is more likely to cause genetic abnormalities. The findings are in this month's Archives of General Psychiatry.

And that's the VOA Special English Health Report, written by Caty Weaver. I'm Steve Ember.