Following the lead of Congress in passing a bill last year establishing the principle of parity for the coverage of mental and physical illnesses, state legislatures around the country are rushing to expand and to fill in what are seen as various loopholes and gaps in the new Federal law. Advocates for the mentally ill, along with family members, and mental health service providers are the principle forces behind the extension of such legislation.

Current and proposed legislation for parity is a Trojan horse for employers, insurers and taxpayers alike. Despite advocates' claims to the contrary, the cost of mandating coverage and protection parity for all the nearly 400 "mental disorders" will be by no means a tiny increase in current health care insurance costs. It will be astronomical for three reasons.

First, parity of coverage between mental and physical illness rests on the utterly fallacious assumption that there is actually such a thing as parity in diagnosis of the two classes of illness. With a few exceptions there is no such thing.

Whatever the American Psychiatric Association may claim, most of the psychiatric disorders in the current edition of the organization's diagnostic manual have nothing in common with cancer or heart disease. The claim that they do is simply fraudulent.

Advocates and mental health service providers argue that they want coverage only for mental illnesses that are "biologically-based." That is a proposal that sounds so reasonable it seems only a real anti-mental health bigot could oppose it.

But there is a big catch here. According to the APA, all of the hundreds of diagnoses in the 1994 edition of the Diagnostic and Statistical manual--the billing bible for psychiatry--are biologically-based. APA makes this claim by fiat alone; there simply is no scientific evidence to support it for the overwhelming majority of "mental disorders."

Attention Deficit Disorder is a case in point. This diagnosis du jour, with some 9 million adult sufferers said to be awaiting imminent identification nation-wide in addition to the millions of children already so diagnosed, has no known cause. There is not even any agreement about probable cause.

Second, many of the putative mental illnesses may not be disorders or diseases at all. As earlier critics like Stuart Kirk and Herb Kutchins have noted, many psychiatric diagnoses merely "medicalize bad behavior," usually with criteria so broadly and vaguely defined that some disorder applies to nearly everyone.

Again, ADD provides an exceptionally apt illustration. ADD is a condition in which a sufferer often fails to pay attention to many of the things in life other people think are important. The symptoms? Failing to pay attention when spoken to. Failing to pay attention to schoolwork. Failing to pay attention to work tasks. Failing to pay attention to organization and detail. Failing to pay attention to just about anything. If failure to pay attention is a recurrent theme in an individual's life, then, voila! he or she suffers from a psychiatrically-defined, biologically-based, mental disorder. Inattentiveness is not just the bad habit of a lifetime, but an authentic mental illness with all of the attendant protections of current law.

Not incidentally, those 9 million potentially diagnosed adult sufferers will require both drug therapy and extensive counseling. It is in the arena of treatment for mental disorders that the third great opportunity for abuse and waste makes its appearance. For most of the APA's "mental disorders"&emdash;whatever those disorders ultimately may turn out to be&emdash;there is no consensually agreed upon treatment that has been scientifically shown to be safe and effective. Nevertheless, under current and proposed legislation, countless unproven varieties of so-called psychotherapy would all be compensable, without any specified limits to the type or length of treatment.

Also, for most of the "disorders," there are no commonly accepted criteria for when a "cure" has been effected. It is strictly up to the therapist and the patient to decide the course of therapy and to determine when enough is enough.

With such a window of opportunity yawning open, some mental health professionals are beginning to talk about the resurgence of unlimited psychoanalysis as the treatment of choice.

Consider the current "treatment" for ADD: counseling intended to teach the disorganized to make lists and put up Post-its with reminders around the workplace. That employers and insurers should cover such "therapy" makes a laughingstock of the concept of medical treatment. How long should it take for this treatment to undo a lifelong habit of inattention to school, to work, to family, to time, to detail, to authority, to whatever the task or person at hand might be? Another lifetime?

Reasonable parity legislation should mandate coverage only for those disorders&emdash;mental or physical&emdash;for which a biological disease or dysfunction has been scientifically specified, and/or only for treatments that have been scientifically shown to be safe and effective. Most "mental disorders" will meet neither criterion.

Parity in mental health coverage is a well-intentioned effort to alleviate real suffering, to make the fullest use possible of the capacities of all American citizens, and to eliminate the stigma attached to mental illness.

Instituting reasonable controls on the implementation of parity is not to deny that there may be true cases of problems with attention that are due to miswiring of the central nervous system, that for a number of mental illnesses there indeed may be solid evidence that they are based on brain dysfunction and/or that they can be effectively treated by scientifically demonstrated methods. Accepting the reality of mental illness does not mean denying the validity of common sense.

Unfortunately, it is this veneer of truth covering the claims of the psychiatrists for the ubiquity and ever-expanding variety of mental illnesses that make their demands for parity between their branch of medicine and the others so insidious. Acceptance of the present definition and scope of mental illness today requires a suspension of disbelief that cannot endure, that will inevitably result in a violent backlash against the death of common sense necessitated by the present situation. Already, the stepped-up attention to fraudulent psychiatric Medicare and Medicaid billing by federal authorities has begun to cast serious suspicion on the whole mental treatment enterprise. Such a backlash will harm the mentally ill with genuine claims on effective treatment for their well-defined illnesses.

In the absence of sensible controls, all total parity means is a financial bonanza for mental health providers who will be held to no standards of accountability for either diagnosis or treatment. The dollars that go in their pockets will be stolen from the most vulnerable of our citizens, those who truly have treatable biologically-based mental illnesses.

(See press release issued by Laurie Flynn, Executive Director, National Alliance for the Mentally Ill, on the Oct. 1 occasion of CA Gov. Gray Davis singing CA's parity measure into law. Appended.)