As chairman of the task force that created the current Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), which came out in 1994, I learned from painful experience how small changes in the definition of mental disorders can create huge, unintended consequences.

Our panel tried hard to be conservative and careful but inadvertently contributed to three false “epidemics” -- attention deficit disorder, autism and childhood bipolar disorder. Clearly, our net was cast too wide and captured many “patients” who might have been far better off never entering the mental health system.

The first draft of the next edition of the DSM, posted for comment with much fanfare last month, is filled with suggestions that would multiply our mistakes and extend the reach of psychiatry dramatically deeper into the ever-shrinking domain of the normal. This wholesale medical imperialization of normality could potentially create tens of millions of innocent bystanders who would be mislabeled as having a mental disorder. The pharmaceutical industry would have a field day -- despite the lack of solid evidence of any effective treatments for these newly proposed diagnoses.

The manual, prepared by the American Psychiatric Assn., is psychiatry’s only official way of deciding who has a “mental disorder” and who is “normal.” The quotes are necessary because this distinction is very hard to make at the fuzzy boundary between the two. If requirements for diagnosing a mental disorder are too stringent, some who need help will be left out; but if they are too loose, normal people will receive unnecessary, expensive and sometimes quite harmful treatment.

Where the DSM-versus-normality boundary is drawn also influences insurance coverage, eligibility for disability and services, and legal status -- to say nothing of stigma and the individual’s sense of personal control and responsibility.

What are some of the most egregious invasions of normality suggested for DSM-V? “Binge eating disorder” is defined as one eating binge per week for three months. (Full disclosure: I, along with more than 6% of the population, would qualify.) “Minor neurocognitive disorder” would capture many people with no more than the expected memory problems of aging. Grieving after the loss of a loved one could frequently be misread as “major depression.” “Mixed anxiety depression” is defined by commonplace symptoms difficult to distinguish from the emotional pains of everyday life.

The recklessly expansive suggestions go on and on. “Attention deficit disorder” would become much more prevalent in adults, encouraging the already rampant use of stimulants for performance enhancement. The “psychosis risk syndrome” would use the presence of strange thinking to predict who would later have a full-blown psychotic episode. But the prediction would be wrong at least three or four times for every time it is correct -- and many misidentified teenagers would receive medications that can cause enormous weight gain, diabetes and shortened life expectancy.

A new category for temper problems could wind up capturing kids with normal tantrums. “Autistic spectrum disorder” probably would expand to encompass every eccentricity. Binge drinkers would be labeled addicts and “behavioral addiction” would be recognized. (If we have “pathological gambling,” can addiction to the Internet be far behind?)

The sexual disorders section is particularly adventurous. “Hypersexuality disorder” would bring great comfort to philanderers wishing to hide the motivation for their exploits behind a psychiatric excuse. “Paraphilic coercive disorder” introduces the novel and dangerous idea that rapists merit a diagnosis of mental disorder if they get special sexual excitement from raping.

Defining the elusive line between mental disorder and normality is not simply a scientific question that can be left in the hands of the experts. The scientific literature is usually limited, never easy to generalize to the real world and always subject to differing interpretations.

Experts have an almost universal tendency to expand their own favorite disorders: Not, as alleged, because of conflicts of interest -- for example, to help drug companies, create new customers or increase research funding -- but rather from a genuine desire to avoid missing suitable patients who might benefit. Unfortunately, this therapeutic zeal creates an enormous blind spot to the great risks that come with overdiagnosis and unnecessary treatment.

This is a societal issue that transcends psychiatry. It is not too late to save normality from DSM-V if the greater public interest is factored into the necessary risk/benefit analyses.

Allen Frances is professor emeritus and former chairman of the department of psychiatry at Duke University.