Sue Goetinck and Tom Siegfried of the Dallas Morning News.

People express their prejudices carefully these days. Sexism and racism and supposedly taboo Jokes about physical handicaps are condemned as tasteless. Nobody shuns cancer patients any more.

But people with mental illness are still fair game. They are satirized on "Seinfeld," stereotyped in serial movies such as "Psycho" and "Halloween" and ridiculed in George Carlin's comedy routines.

When John du Pont was arrested on murder charges, TV comedians exploited his mental illness for a few laughs. When rock star Kurt Cobain, who suffered from depression, committed suicide, "60 Minutes"commentator Andy Rooney derided him for not having a good enough reason.

George Will, a Pulitzer Prize-winning syndicated columnist,lampooned the Americans With Disabilities Act for protecting people with mental disorders, (U.S. House Speaker Newt Gingrich, in his book on renewing America, lumped the mentally ill in with dangerous criminals.)

"I'm so used to cruel and insensitive comments about mental illness that it doesn't surprise me," said Dr. Kay Redfield Jamison, a psychiatrist at Johns Hopkins University in Baltimore. "It's easy to make fun of."

But it's apparently not so easy to understand. Mockery, discrimination and stigma persist despite scientific research showing mental illnesses to be as real and as serious as any other sickness.

Like cancer, diabetes and heart disease, mental illness can be chronic, debilitating or fatal. Even so, most health insurance plans don't offer equal coverage for mental disorders.

Compelling scientific evidence shows that mental illness is based in biology. Hallucinations in people with schizophrenia are allayed by medicines. Lithium tablets tame the terrifying emotional ups and downs afflicting victims of manic depression. Brain scans show abnormal biochemistry in people who are depressed.

"Mental illnesses are brain diseases," said Steven Hyman, director of the National Institute of Mental Health." Based on biomedical research, there is absolutely no justification for separating out mental disorders from other serious brain disorders. They are brain diseases just as a stroke or a brain tumor is a brain disease.

Yet when it comes to mental illness, society has not caught up to science. "The world's history has been one of fear and misunderstanding and superstition around mental illnesses," said Michael Faenza, president of the National Mental Health Association. "There's still a lot of misunderstanding. About half the folks out there think that mental illnesses are problems that have to do with character and self-discipline.

In one poll, for the National Depressive and Manic-Depressive Association, nearly two out of three respondents didn't know that mental illnesses have physiological causes. One respondent in four thought people brought depression on themselves. Many people think depression is no more than the blues, instead of a serious clinical disorder.

Despite the mountains of research, these and other misconceptions about mental illness are slow to die, mental health professionals say. And, they say, those misconceptions contribute to neglect of a major public health problem.

As many as one in four Americans will suffer a serious mental disorder at some point in their life; in any single year, mental illness of some sort afflicts more than five million Americans. The annual cost of treatment, based on 1990 figures, exceeds $67 billion - more than 11 percent of the nation's total health care bill.

Adding the costs of social services, disability payments, lost productivity and premature death pushes the annual cost of mental illness to more than $150 billion, according to NIMH.

The human costs are not recorded only in dollars, but also in deaths. Between 15 and 20 percent of people with major depression commit suicide, and victims of other mental disorders are at a high risk for suicide as well. "Most suicide attempts are tied to mental illness - 95 percent," said John Rush, a psychiatrist at the University of Texas Southwestern Medical Center at Dallas.

Suicide often carries stigma similar to that of mental illness itself. Such stigma stems from a bias in society against the belief that mental illness are really manifestations of physical problems, said Dr. Kenneth Altshuler, chairman of the psychiatry department at UT Southwestern.

"Because people can do so much with their minds," he said, "some think they should be able to do everything."

"To me that's the real reason that mental illness has the stigma it does," Dr. Altshuler said. "We have a tremendous investment in the power of our minds. Wherever you go in the country or the world, you see people who have these ideas - that I can control it with my mind."

But people with mental illness say willpower simply doesn't work.

"People think for some reason you have control over it," said Rebecca Parks, a 42-year-old Dallas resident with schizophrenia. "You do not. Without the medication you do not."

Parks, who works at a bookstore, said she first became ill with schizophrenia when she was 23. With treatment, she hasn't had a psychotic episode for six years, she said. But at first, she said, she blamed herself.

"I felt like such a failure and so weird that I was doing crazy things. Why couldn't I just stop?" she said. "Back when I first got sick, even the doctors didn't know what caused schizophrenia. I had a doctor tell me that it was my way to get what I wanted from my family. Nobody really thought it was biological back then."

Even now, in the face of scientific evidence and advances in medicine, the blame persists. Dianne Shirley, a sales manager who lives in Dallas, said many of her co-workers don't believe that her son, who has been diagnosed with schizophrenia, has a medical condition. Because he also has drug abuse problems, people write off his mental illness and blame it on the drugs, she said.

But Shirley said she thinks her son turned to drugs in an attempt to self-medicate his illness.

"There's not a person in the world who would say, "I want to be mentally ill," she said. Even among psychiatrists, old biases linger. In her book "An Unquiet Mind," Johns Hopkins' Dr. Jamison describes a colleague's reaction when she told him that she had manic depression.

Her colleague said he was "deeply disappointed" that she wasn't strong enough to resist a suicide attempt, Jamison writes. And even thought most of her colleagues are psychiatrists, it wasn't easy to reveal her illness, Jamison said in an interview. In fact, she doesn't necessarily recommend it.

"Most people aren't in that position (having psychiatrists as colleagues)," she said. "And it's terribly personal."

Scientists don't necessarily understand mental illness either, said Kenneth Kendler, a psychiatrist at the medical College of Virginia in Richmond.

"It bothers me immensely to sit on human subjects committees where people are approving very invasive treatments or research on cancer and you come to somebody wanting to do research on schizophrenia and you get statements like, "Well, that's just an emotional problem," he said.

People's reactions to mental illnesses may be inappropriate because such illnesses, especially the most severe, are hard to fathom, said Dr. Joel Feiner, training and clinical director of Mental Health Connections, a collaboration between the Dallas County Mental Health and Mental Retardation Center and UT Southwestern's psychiatry department.

"These are people who are pointing out to us things that we're very afraid of in ourselves," Feiner said. "And that is losing control and going to extremes and being banished.

"It's confounding. And when we can't understand something about ourselves, and about human nature, I think we have different ways to deal with it," he said. "We jump in and embrace it and make a career out of it like I do, or you investigate it like other people do, or you avoid it and laugh at it and demean it and make believe it's very different than you." Or you fight.

In February, the National Alliance for the Mentally Ill launched a five-year campaign to fight the stigma of mental illness. The group plans to use public service announcements, rallies and local publicity to inform the public about mental illnesses, said NAMI spokeswoman Farrel Fitch.

Besides fighting stigma, NAMI wants to put mental illnesses on equal footing with other diseases in health benefit plans. "Most people don't know, until they have to know, that these disorders aren't covered equally," Fitch said.