SHOULD PEOPLE be expected to know when potential sex partners have ''mental illness'' and refrain from sexual intercourse with them even if they give consent?
This was the point at issue in the sexual-assault conviction last week of Mark Peterson in a Wisconsin criminal court. Peterson had sexual intercourse with ''Sarah,'' a woman who, the prosecution argued, suffered from a ''mental illness'' called ''multiple personality disorder.'' The prosecutor, district attorney Joseph Paulus, professed satisfaction that ''we did something for mentally ill people,'' and that the consequence should be expanded legal protections for those who have ''mental illness.'' As Mr. Paulus appraised the defendant's intentions: ''He knew about it [the mental illness] before, found out about it and preyed on it to get what he wanted.''
Mr. Paulus' intentions may be as good as Peterson's were bad, but he completely misunderstands just how ambiguous the term ''mental illness'' is, particularly as applied to disputed notions such as ''multiple personality disorder.''
''Mental illness'' is a pseudo-medical term: None of the mental illnesses described in the American Psychiatric Association's diagnostic manual is diagnosed by laboratory tests. Moreover, the labeling of specific behavioral problems as ''mental illness'' is in great dispute: Some psychiatrists apply it quite freely, some with great parsimony, and some claim that most ''mental illnesses'' are not illnesses at all, but ''problems in living.''
Also in dispute is the connection between ''mental illness'' and decisional competence. There clearly are people -- ''mentally ill'' or not -- who are incapable of making decisions for themselves. There is nothing wrong with the law's requiring adult citizens to exercise some responsibility for determining whether people with whom they intend to have sex are capable of giving consent. Most modern statutes protect those who cannot reasonably give consent, such as children or persons who are unconscious or severely mentally retarded.
The Wisconsin statute under which Mark Peterson was prosecuted reads as follows: ''Whoever does any of the following is guilty of a Class C felony . . . (c) Has sexual contact or sexual intercourse with a person who suffers from a mental illness or mental deficiency which renders that person temporarily or permanently incapable of appraising the person's conduct, and the defendant knows of such condition.''
Under Wisconsin law, ''consent is not an issue'' under this section as well as under those prohibiting sex with an unconscious person or sex between an employee of a state hospital and a patient. The effect of these sections is to make sexual assault in such situations virtually a strict-liability offense, that is, one in which the defendant's intentions are irrelevant if it can be shown that the victim fits into one of the three categories and that the defendant knew it.
But determining if someone is ''mentally ill'' is entirely different from determining if someone is unconscious or a patient in a hospital where one is employed.
Lester Judd, director of the National Institute of Mental Health, claims that there are ''27 million adult Americans with a diagnosable mental illness.'' What are the implications for those who believe, as Peterson's prosecutor stated, that the ''mentally ill'' must be protected? Would it be a sexual felony to have sex with any of these 27 million people if one knows of their condition? And what does it take for a person to ''know of such condition?''
In the current case, it took the young woman's therapists four years to settle on the diagnosis of ''multiple personality disorder.'' In addition, the prosecution showed the jury scholarly articles and visual displays allegedly demonstrating brain-wave changes among different personalities of those with the disorder.
Peterson's ''knowledge'' of Sarah's ''mental illness'' supposedly came from his being apprised of it by Sarah's neighbor, as well as by Sarah herself. Peterson denies the neighbor so apprised him, but even if she did, should a neighbor's allegation that someone is mentally ill be accepted without reservation? And, more troubling, should such evidence suffice as a basis for a felony conviction?
Even for traditional psychiatrists, ''mental illness'' does not automatically mean that sufferers are incapable of ''appraising'' their own conduct or giving consent to sex. The Wisconsin law thus not only requires a person to recognize a diagnosis of ''mental illness'' that trained psychiatrists may not agree on, but also to determine when that ''mental illness'' has rendered a person incapable to ''appraise [her] own conduct,'' even when she appears to act voluntarily.
State laws reasonably require restraint when the ability to give consent is manifestly impaired, as in the case of unconsciousness. Such laws strike a sensible balance between protecting incompetents against sexual abuse and protecting potential defendants against unfair criminal prosecutions in ambiguous circumstances. Let's hope that, contrary to Mr. Paulus' wishes, other states do not expand such protections to all of those nebulously defined as ''mentally ill.''
Mr. Vatz teaches rhetoric and communication at Towson State University. Mr. Weinberg teaches in the Graduate School of Public and International Affairs at the University of Pittsburgh.