The hate behind two recent killing sprees was driven by paranoid schizophrenia. The correct response, say E. Fuller Torrey and Mary T. Zdanowicz, is to make treatment for mental illness mandatory.

In response to the killings of five individuals near Pittsburgh, President Clinton has called for national legislation to ban hate crimes. His call for action would be much more effective if he instead called for legislation to ban lack-of-treatment crimes.

Richard Baumhammers, a 34-year-old lawyer, has been charged with killing five members of minority groups on April 28. According to media accounts, Baumhammers exhibited typical symptoms of paranoid schizophrenia, including a belief that he was being followed and had been poisoned. He had also been treated at a local hospital for his psychiatric disorder.

Ronald Taylor has been charged with killing three people and wounding two others in Wilkinsburg on March 1. Taylor, who is black, appeared to select his victims because they were white. His actions were also widely discussed as a hate crime. Taylor has subsequently been diagnosed with paranoid schizophrenia and has been found to be not mentally competent to stand trial. He had been hospitalized several times for his psychiatric illness and was last released six months prior to the shootings.

What is behind these tragedies? It is easy to attribute them to "racism" or "inadequate gun control," but that is to miss the essence of the crimes. Both men have schizophrenia, a biological disease of the brain that causes delusional and illogical thinking. Their killings and their racism are both products of the delusional thinking caused by their illness. If their schizophrenia had been adequately treated, these crimes would never have happened.

Let us be clear that individuals with schizophrenia who are receiving treatment are not more dangerous than the general population. Multiple studies have demonstrated that.

But those who are not being treated are more dangerous.

Schizophrenia is a treatable illness but requires the taking of medication for long periods of time. Because of the nature of the brain damage caused by schizophrenia, many individuals with the disease are not aware that they are sick and therefore refuse to take medication. They will take it only when placed on some form of assisted treatment such as outpatient commitment.

Although details of the treatment of Baumhammers and Taylor have not been made public, it is virtually certain that they were not taking the medication they needed to remain well. As in most states, the standard in Pennsylvania for involuntary treatment of an individual with schizophrenia is very strict insofar as the person must present a "clear and present danger to self or others."

Pennsylvania has an outpatient commitment law but, like those in most states, it is virtually never used. Individuals like Baumhammers and Taylor usually give warning of their potential dangerousness. Taylor advised officials to contact his former counselors "to let them know I finally followed through with my plan."

Senseless multiple homicides such as those committed by Baumhammers and Taylor are becoming more common. A recent New York Times study reported that, according to FBI statistics, multiple homicides (three or more victims) increased 46 percent in the 1990-1997 period compared with the 1976-1989 period. And they will continue to increase until we change state commitment laws to accord with modern medical knowledge and the needs of the patients.