The Nature of Mental Disorders
The terms “mental disorder,” “mental illness,” and “psychopathology” are often used interchangeably by those in psychology and related fields; all refer to the study of unusual or abnormal behaviors. Unlike terms and concepts in many of the physical sciences, however, there is not a single, agreed-upon by all operational definition for these terms. The primary definitional conflict hinges on this question: Can mental disorders be defined as a scientific term, or are they instead socially constructed?

This lack of a single definition can lead to confusion and communication problems both when mental health professionals, such as psychologists, psychiatrists, counselors, or social workers, attempt to talk to each other and to the general public. As a result, mental disorders are used and defined in a variety of ways. Before beginning our examination of anxiety disorders, we must discuss these definitions and decide which one (or ones) will guide this book. Below are descriptions of the most common perspectives.

Mental Disorders as Statistical Deviance

The statistical deviance perspective has enormous common sense appeal, as it involves defining abnormal behavior by comparing an individual’s behavior to the frequency of occurrence of the same behavior in the general population. A behavior is considered abnormal if it occurs rarely or infrequently in the general population. This definition lends itself very well to measurement, as researchers and clinicians can administer objective assessments to clients and get accurate measurements of just how far their depression, anxiety, hyperactivity, and so on are from the norm. As such, this definition is often seen as highly scientific.

Unfortunately, several problems are apparent when this model is examined closely. First, who determines how far from the norm is too far from the norm? It is not as if there is a stone tablet handed down from the psychopathology gods that has “Behaviors that are two or more standard deviations from the norm shall be considered abnormal” written on it. Instead, researchers and clinicians make that decision. Often, behaviors are considered “abnormal” if they occur in less than 5% of the population (1.645 standard deviations from the mean), but this is an entirely arbitrary cutoff. Another concern is that the tests that measure one’s deviation are developed from within a particular cultural framework. In other words, there is not an objective, scientific definition of “obsessive-compulsive disorder,” there is only the definition that the researchers developing the measure have (and someone else may not agree with it).

It is also worth noting that when viewing behavior, both sides of the normal curve would be considered “abnormal.” So, according to this model, both someone with very high and very low general anxiety would be considered abnormal. In the real world, though, it is usually only one tail of the curve that is viewed as problematic or abnormal. For illustrative purposes, picture someone with an IQ of 70 and another person with an IQ of 130. On a scale where 100 is the average, with a standard deviation of 15, both are equally deviant from “normal” intelligence. Most people, however, would only consider the person with extremely low IQ to have a mental disorder, another problem with this conception.

Mental Disorders as Social Deviance

In the social deviance perspective, behavior is deemed abnormal if it deviates greatly from the accepted social standards, values, and norms of an individual’s culture. This is different from the statistical perspective described above, as this method is uninterested in the actual norms of the population. This is because a population may have accepted standards that the majority of the culture do not actually meet. An example of this would be using alcohol and tobacco prior to the legal age of use, which would be considered unlawful and socially unacceptable, yet major surveys show that over 75% of high school seniors have consumed alcohol.
The problems with the social norms perspective are fairly obvious. First, there is little to no objective validity, due to individuals and groups even within the same culture having different ideas of what is socially acceptable. Second, what is acceptable at one point in time can become unacceptable with the passage of time, or vice versa. Until 1973, for example, homosexuality was classified as a diagnosable mental disorder by the American Psychiatric Association, rather than being recognized as a normal variation of sexual orientation. Finally, the different morals and standards of disparate cultural groups would mean that what was normal in one country or region would be considered abnormal in another.

Mental Disorders as Maladaptive Behavior

The maladaptive behavior perspective attempts to classify as mental disorders those behaviors that are dysfunctional. This refers to the effectiveness or ineffectiveness of a behavior in dealing with challenges or accomplishing goals. Typically discussed maladaptive behaviors include physically harmful behaviors, behaviors that prevent the person from taking care of themselves, those that prevent communication with others, and those that interfere with social bonding and relationships. As with our other perspectives, there are major concerns with this one.

First, how adaptive a behavior is hard to objectively quantify. This is due to the fact that the adaptive level of any particular behavior is based on both the situation and one’s subjective judgment. If a person is engaging in coercive behaviors, stealing, and lying to others, most people would say those are maladaptive behaviors (and depending on his age, qualify you for a diagnosis of Conduct Disorder or Antisocial Personality Disorder). But what if you learn that he was doing this to obtain food or medicine for his family? Would that still be maladaptive? One’s culture also plays a large role in determining the adaptiveness of a behavior.

For instance, in many Native American tribes, it is considered disrespectful to look an elder directly in the eye when talking to them. In other cultures, though, it would be considered disrespectful to not look them in the eye. Finally, this perspective clashes mightily with the statistical deviance perspective, in that statistically deviant behaviors (e.g., an IQ higher than 99% of the population) can be highly adaptive, and that numerous maladaptive behaviors (such as fear of public speaking) are quite common in the population as a whole.

Dimensional vs. Categorical Models of Mental Disorders

Another, different way to think about mental disorders is captured in the concept of categories versus dimensions. In a categorical model, psychopathology is dichotomous, either being present or not being present. In other words, you either have a mental disorder, or you don’t, there is no in-between. Dimensional models, on the other hand, acknowledge the fact that the vast majority of human behavior exists on a continuum, rather than the polarized view of the categorical model. What tends to be labeled as abnormal and unusual are merely the far ends of this normal curve of behavior. In this model, then, mental disorders are just extreme variations of normal psychological phenomena or problems that many or most of us experience.

The dimensional model has a very large amount of scientific support, particularly in the area of personality disorders. Support has been found for dimensional models of many other disorders, though, including anxiety, depressive episodes, and even psychotic disorders. Unfortunately, however, the real-world often requires caseness or non-caseness. In many instances one must be diagnosed with a particular mental disorder to obtain certain things, such as insurance reimbursement, special services at school, or disability benefits. This, subsequently, creates a tension between the need for categories and the lack of scientific support for them.

DSM Definitions of Mental Disorder

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is published by the American Psychiatric Association, and is the most widely used classification system of mental disorders in the United States (outside of the U.S., both the DSM and the International Classifications of Disease, or ICD, are used). It provides diagnostic criteria for almost 300 mental disorders. But how exactly does it define mental disorder? In the most recent edition, published in 1994, the following features are considered descriptive of a mental disorder:

  • a) A clinically significant behavioral or psychological syndrome or pattern that occurs in an individual
  • b) Is associated with present distress (e.g., a painful symptom) or disability (i.e., impairment in one or more important areas of functioning) or with a significantly increased risk of suffering death, pain, disability, or an important loss of freedom
  • c) Must not be merely an expectable and culturally sanctioned response to a particular event, for example, the death of a loved one
  • d) A manifestation of a behavioral, psychological, or biological dysfunction in the individual
  • e) Neither deviant behavior (e.g., political, religious, or sexual) nor conflicts that are primarily between the individual and society are mental disorders unless the deviance or conflict is a symptom of a dysfunction in the individual

The DSM-IV goes on to state, though, that “no definition adequately specifies precise boundaries for the concept of "mental disorder” and that “the concept of mental disorder (like many other concepts in medicine and science) lacks a consistent operational definition that covers all situations.” Even with those caveats, this definition has considerable concerns: What exactly does “clinically significant” mean? How much distress is enough distress and who determines that? Who says what is or is not “culturally sanctioned”? And last, but perhaps most important, what defines a “behavioral or psychological syndrome or pattern”?

The categorical nature of the DSM-IV is also of concern, and the authors even state that they recognize the actual, dimensional nature of mental disorders, but due to the need for caseness (as described above) must operate in a categorical nature. This, in turn, contributes to the high amount of diagnostic overlap, or comorbidity, present in clinical populations. In one of the most well-conducted studies to examine this issue, Ronald Kessler and his research team (2005) found that 26.2% of Americans met criteria for a mental disorder; of these, 45% met criteria for two or more disorders.

These concerns and questions are certainly on the minds of many researchers and clinicians, and in fact a special group was assembled to rework the definition of a mental disorder for the upcoming revision of the DSM, the DSM-5, which is scheduled to be published in May 2013. The proposed revision, which was made available both online at and in an article by D.J. Stein and colleagues (2010), is as follows.

  • a) A behavioral or psychological syndrome or pattern that occurs in an individual
  • b) That reflects an underlying psychobiological dysfunction
  • c) The consequences of which are clinically significant distress (e.g., a painful symptom) or disability (i.e., impairment in one or more important areas of functioning)
  • d) Must not be merely an expectable response to common stressors and losses (for example, the loss of a loved one) or a culturally sanctioned response to a particular event (for example, trance states in religious rituals)
  • e) That is not primarily a result of social deviance or conflicts with society

As in the DSM-IV definition, there are other proposed caveats or considerations. A mental disorder should, by this definition, have diagnostic validity, clinical utility, and be differentiated from other, similar disorders. In addition, it is again acknowledged that there is no precise boundary between normality and mental disorders, and that the addition or deletion of a condition from the DSM should have substantial potential benefits which outweigh potential harms. While this proposed definition, and the revisions to many disorders that actually specify measures to determine severity and symptom level, are certainly an improvement over the DSM-IV (which was, in turn an improvement over earlier versions), there are still concerns over this definition. Specifically, will such severity indicators be used in real-world practice, and how will the introduction of such dimensionality impact treatment, reimbursement, and diagnostic practices? Will the improved diagnostic categories decrease the amount of overlap and comorbidity seen in mental health settings?

What to Do?
Given the problems with all of the preceding definitions of a mental disorder, one might begin to question the need for such a term or concept. After all, if it cannot be easily and accurately defined, what use is it? If the DSM categories are problematic, then why diagnose using them? The simple answer is “We use them because we need them.”

Humans are natural categorizers, with a need to group and order things that we encounter. Our diagnostic typologies reflect this underlying need. It is much easier to understand and communicate to someone that a client is diagnosed with obsessive-compulsive disorder and generalized anxiety than to say something like “Their general anxiety level is at the 87th percentile, while they also have more obsessive, intrusive thoughts than 94% of the population and a subsequent rate of compulsive, anxiety reducing behaviors greater than all but 16% of their peers.” In many cases, dimensional models of psychopathology, although perhaps more accurate, may simply be too confusing and/or complex to be useful in the real world.

Doing diagnostic work, and giving a patient a diagnosis based on presenting symptoms and lab findings, is an enormous part of all health professions. This is true even though dimensional models actually make more sense for almost all of what are called diseases (e.g., “Your blood pressure is higher than 95% of males your age, weight, and fitness level” rather than “You have high blood pressure.”) Given clinical psychology’s development and outgrowth from medicine, it makes sense that diagnosis would be part of our heritage. In many ways, it also establishes the credibility of psychiatry and clinical psychology by allowing these professions to stake out their “territory.” Having something like the DSM essentially says “These problems and dysfunctions are the domain of psychiatry, so you other types of health providers back off.” Losing diagnoses as part of the profession would mean that, in essence, we were losing our domain of health care. These reasons are, of course, in addition to the facts discussed previously about how real-life requires caseness or non-caseness in many occasions.

So, we as a profession and a society need definitions of mental disorders, and yet there does not appear to be a scientific consensus or definition on what a mental disorder actually is. So if there can be no truly scientific definition, what are we left with?

Mental Disorders as Social Constructions

Mental disorders, mental illness, and psychopathology are best understood as products of our history and culture, and should try to be defined as some sort of universal, scientific construct. Mental disorders are, in a very real sense, invented. This does not, however, mean that they are not real. Instead, our conception of what is and is not normal behavior is influenced by everything from social and cultural forces, to politics and economics, to which professional groups have the most influence and clout at the time new definitions are being written. Mental disorders, then, are social constructs, a concept that is constructed by a particular group (in this case, the committee members of the DSM Work Groups, who are in turn influenced by researchers, clinicians, politicians, lay people, industry, religious beliefs, and more).

Accepting that mental disorders are a social construct, for some, implies that they are somehow fake or unimportant. Nothing, in fact, could be further from the truth. To put this in perspective, consider a number of other social constructs: love, beauty, race, poverty, wealth, physical disease. Each of those is constructed, and you will see different definitions of each when moving across time and between cultures.1 This does not rob any of them of their importance, or make any of them less real. The same is true of mental disorders.


Mental disorders are hard to define, even by those who make it their life’s work to study and treat them. Although there are certainly faults and flaws with the most widely used and social constructed definition, that of the DSM, the drawn boundary between normal and abnormal are essential to clinical psychology as a profession, persons with mental illness, and society as a whole.

Key References

  • American Psychiatric Association (2000). Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. Washington DC: Author.
  • American Psychiatric Association (2011). Definition of a mental disorder. Retrieved from on June 28, 2011.
  • Bergner, R. M. (1997). What is psychopathology? And so what? Clinical Psychology: Science and Practice, 4, 235-248.
  • Brown, P. (1995). Naming and framing: The social construction of diagnosis and illness. Journal of Health and Social Behavior, 35 (Extra Issue), 34-52.
  • Eisenberg, L. (1988). The social construction of mental illness. Psychological Medicine, 18, 1-9.
  • Maddux, J.E., Gosselin, J.T., & Winstead, B.A. (2005). Conceptions of psychopathology: A social constructionist perspective. In J.E. Maddox & B.A. Winstead (Eds.), Psychopathology: foundations for a contemporary understanding. Mahwah, NJ: Lawrence Erlbaum Associates.
  • Stein, D.J., Phillips, K.A., Bolton, D., Fulford, K.W.M., Sadler, J.Z., & Kendler, K.S. (2010). What is a mental/psychiatric disorder? From DSM‐IV to DSM‐V. Psychological Medicine, 40, 1759‐1765.
  • Widiger, T. A. (1997). The construct of mental disorder. Clinical Psychology: Science and Practice, 4, 262-266.