Essential understandings

  • Many factors may affect the reliability and validity of diagnosis
  • There are ethical considerations for diagnosing mental illness.
  • Concepts of normality and the classification of psychological disorders is not universal.

Concepts of normality and abnormality

The study of psychological disorders is called “abnormal psychology”. Abnormal behaviour presents psychologists with a difficult task: it is difficult to define and therefore it is difficult to diagnose because it is, to a large extent, based on the symptoms people exhibit or report. Making a correct diagnosis is extremely important because this determines the treatment people receive. Psychiatrists and psychologists use a standardized system called a diagnostic manual to help them, but such a system is not without faults. Since there is no clear definition of normality—or abnormality—and symptoms of the same psychological disorders may vary not only between individuals but also between social and cultural groups, it is clear that a psychiatric diagnosis may be biased or even wrong. Definitions of normality and abnormality can also change over time.

Often, a decision about whether or not an individual’s behaviour is abnormal depends on a series of value judgments based on subjective impressions. Definitions of “normality” are part of the diagnostic process, which is why it is considered important to establish some objective criteria. Normality is often linked to the concept of “mental health” – the psychological state of someone who is functioning at a satisfactory level of emotional and behavioral adjustment.  

To make a diagnosis, the clinician must rely on self-reported data from the person seeking assistance, physiological testing, clinical observation and the diagnostic tools of classification systems.  Diagnosis is not simply a subjective assessment by the clinician.  Data triangulation is used in order to increase the validity the diagnosis with an attempt at minimizing researcher bias. In addition, the development of diagnostic manuals to help classify disorders is seen as an improvement in the objectivity of diagnosis.  In spite of this, we will see that several factors influence the level of objectivity in diagnosis.

Data triangulation attempts to validate data by obtaining data from two or more sources.

Conceptual definitions

When psychologists discuss abnormality, they use two types of definitions.  Conceptual definitions are to a large extent based on societal norms. These definitions include a statistical deviation from the norm, deviation from social norms or deviation from what is considered to be “mental health.”  There are several problems with using “deviation from the norm” as a criterion for labeling a behaviour as “abnormal.”

Which of following behaviours would you consider to be abnormal?

  • Alcoholism
  • Being able to see sounds and hear colours
  • Being overextended; taking on too many projects or activities
  • Having conversations with dead ancestors
  • Homosexuality

As you can see, if we apply conceptual definitions, we have some problems with this list. Statistical deviation argues that the least common behaviours are those that should be considered “abnormal.”  But in this case, alcoholism is relatively common. According to a 2014 World Health Organization report, 31% of Russian males and 29.1% of Americans suffer from Alcohol Use Disorder at some point in their lives.  This is true of several of the disorders that we will study in this book.  The National Institute of Mental Health [NIMH] has found that by age thirty-two, 50% of the general population in the US has experienced an anxiety disorder and 40% for depression. Based on these numbers and the criteria of statistical deviation we would have to ask if it is perhaps rather "normality" that is abnormal.   

ATL: Thinking critically

Being able to see sounds and hear colours is a phenomenon known as synesthesia. About .05% of the population experiences the world in this way. 

Although it is abnormal from a statistical point of view, it is not recognized as a disorder.

  1. How do you think that having synesthesia would affect how you live your life?
  2. Why do you think that psychologists do not label synesthesia as a disorder?Do you think that they are correct to do so?

Defining abnormal behaviour as social deviation is also problematic.  Morality and cultural practices determine social norms and they change over time. The orthodox view in the West was that homosexuality was abnormal and it was classified as a mental illness. The stories of famous homosexuals in the past – for example, Oscar Wilde and Alan Turing - show that Western society did not accept homosexuality.  It was criminal behavior and seen as immoral and abnormal. The older versions of the diagnostic system reflected that view. In the 1960’s aversion therapy was used to treat homosexuality; gay men were given electric shock therapy while being exposed to homoerotic imagery. This therapy was not successful. Some progress was made in the DSM-IV (1994) where homosexuality was classified as a disorder only when one had “persistent and marked distress about one’s sexual orientation”.

Over the past fifty years, there has been a major societal change in many parts of the world in people’s attitudes toward homosexuality. Although there are still a number of societies in which homosexuality is seen as a social deviation, since 1973 psychologists no longer classify homosexuality as a disorder. However, this example illustrates the problem in classifying what is normal and what is abnormal.

Referring back to the list above, taking on many projects – what is often referred to as “multi-tasking” -  is highly valued in Western society.  These people are seen as highly effective and are often desirable in the workplace.  However, modern research on stress and mental health shows that although society may promote such behaviours, this may actually not be a healthy behaviour.

Culture also plays a key role in what is considered normal.  In Western culture, hearing voices and having conversations with those voices, is considered a symptom specific to schizophrenia. Luhrmann et al (2014) has argued that this is due to cultural differences.  The team carried out interviews in Ghana of 20 people reporting that they heard voices from God or other spirits.  They did not feel that this was a sign of psychiatric illness because their culture believes that spirits can talk to us.  This example clearly shows that what is considered a sign of abnormal behaviour in one culture may be considered normal and healthy in another.

ATL: Reflection

The study by Luhrmann et al (2014) may seem strange to people who are not from Ghana.  It is easy for us to think that different cultures may "misunderstand" their symptoms and that those of us who "understand psychology" know that hearing voices is an actual concern. 

Watch the following video where Eleanore Longden describes her personal experience of hearing voices.

After watching this video, what do you think?  Is hearing voices an abnormal behaviour?  Do you agree with Eleanor Longden?  Was she mistreated because of her symptoms?

Finally, there is the definition that is based on deviation from optimal health norms.  Jahoda (1958) suggested that we could define positive mental health in order to recognize mental illness. The key features would be: self-acceptance, potential for growth and development; autonomy; accurate perception of reality; environmental competence; and positive interpersonal relationships.

It is difficult to define these criteria precisely, so the question is what they actually mean. Jahoda, for example, stated that the unemployed were deprived of many of these characteristics and that this might account for much of the reported mental ill-health among unemployed people.

Although Jahoda's approach appears to be more objective than the first two, it also is problematic. First, how does one measure a person’s "potential for growth and development" or "self-acceptance?" The theory is also ethnocentric; Jahoda is writing from the perspective of an individualistic society where independence, personal growth and self-expression are highly valued. Finally, there is agreement that mental health should be seen on a continuum - that is, each and every one of us move between very positive mental health and negative mental health. Therefore, modern psychology tends to focus on the extent and duration of symptoms in order to determine whether the behaviour should actually be seen as a "disorder."  Jahoda’s list of positive mental health criteria seems intuitively appealing, but if the criteria were applied, most of us would seem somehow abnormal. Consequently it may be difficult - if not impossible - to establish universal criteria for what is considered abnormal or normal for that matter.

Practical definitions

Practical definitions are based on what can be observed, rather than variance from a norm.  Often these definitions are based on one's ability to "function" in society. This is why abnormal psychology is also referred to as the psychology of dysfunctional behaviour. Dysfunction refers to the disruption in one's ability to work and/or to conduct satisfying relations with people. A great part of this dysfunction is the distress that the individual experiences as a result of his/her abnormality.

Rosenhan & Seligman (1989) suggested that there are seven criteria that could be used to decide whether a person’s behaviour is normal.

Rosenhan & Seligman's Criteria for Abnormal Behaviour
IrrationalityUnable to communicate in a reasonable manner.
MaladaptivenessEngages in behaviours that make life difficult.
Observer discomfortActs in a way that is difficult to watch or makes others feel uneasy.
SufferingExperiences distress or discomfort
UnpredictabilityActs in a way that is unexpected by him/herself or others.
Violation of community standardsHabitually breaks the accepted ethical and moral standards of the culture.
Vividness & unconventionalityExperiences things that are different from most people.

These criteria demonstrate the fine line between defining abnormality in ways that focus on distress to the individual, and defining it in terms of what is or is not acceptable to society. The danger of social judgments is that they often fail to consider the diversity in how people live their lives. There is an increasing awareness of how psychiatric diagnosis of ethnic minorities has been misapplied because doctors do not understand the cultural norms of the groups people come from.

During a diagnostic procedure, psychiatrists focus on symptoms that help them to identify a disorder and decide whether one's behaviour is "abnormal" and/or "dysfunctional" or not. Based on the self-reported symptoms of the individual, as well as clinical observations, psychometric testing and physiological testing, a diagnosis is determined by comparing these symptoms to a standardized classification system, such as the DSM or the ICD. As we will discuss below, using checklists of symptoms is problematic and can lead to biases on the behalf of the psychiatrist.

ATL: Thinking critically

According to the latest DSM-V, there is no such thing as an official diagnosis of "Internet Use Disorder." However, it is listed as a possible diagnosis in the future. According to the DSM-V, more research is necessary before this can be labeled as an official disorder.

Based on the definitions in this chapter, do you think that Internet Use Disorder could be considered an official disorder? What would be the evidence you would use for your decision?  What symptoms would you include as important for an official diagnosis?

Checking for understanding

Which of the following is not a problem of diagnosis?

The fact that not everyone improves after being diagnosed is not a problem with diagnosis, but with treatment.


How can we increase the validity of a diagnosis?

By obtaining data from several different sources, it is more likely that the diagnosis will be valid. A single interview, for example, could lead to rather low validity of a diagnosis.


Why is statistical deviation a limited system for deciding if a behavior is “abnormal?”

The problem is that some behaviours, like alcohol abuse, are actually quite common.  This would mean that it is not an abnormal behaviour statistically, but it still has a negative effect on the health of an individual.


Which of the following is not true of Jahoda’s Optiminal Mental Health model?

The criteria are not clearly defined and are thus difficult to measure in a standardized manner.


What is meant the sentence “Mental health should be seen as a continuum?”



What is the key difference between practical definitions and conceptual definitions? 



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Classification systems  

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