Page Navigation - Go to: site index | start of page content | links to sections in this module | this section's glossary | links to related material
Stories about the lives we've made

module:Measuring the unmeasurable

An introduction to psychology

page:Defining mental illness

How do psychologists define abnormality? Defining abnormal behaviour and mental disorders is not an exact process. We should always consider the fact that psychology deals with individuals and everyone is different. Psychologists therefore use a variety of criteria and definitions that fit not only the person but also their behaviour and the context in which that behaviour occurs. These are as follows:

Deviation from statistical norms
Human behaviour can be seen as abnormal if it falls outside a range that is considered statistically typical. People are quite literally seen as being outside the range of normal behaviour. Those who focus on this statistical aspect of abnormal behaviour typically measure specific characteristics of individuals - for example, personality traits or IQ - and the statistical distribution of these characteristics within the population.

Normal distribution curve for IQ

This type of population distribution, the normal distribution curve, depicts the majority of people as being in the middle as far as any particular characteristic is concerned, with fewer people falling at either extreme. 'Normal' is the average, or statistically most frequent. An assertion that a person is statistically normal implies that they do not deviate from the numerical average in a particular trait or behaviour pattern.

Deviation from social norms
Certain behaviours are not merely acceptable in society, but also often expected in certain situations. Most members of society are aware of these social norms and adjust their behaviour accordingly. Those of us who break these norms are often seen as abnormal, or in extreme cases mentally ill. This approach takes into account the social desirability of behaviour, as social norms identify those behaviours that are considered desirable for both the individual and society. The wild behaviour, manic and strange antics of the schizophrenic fit this definition.

Dysfunctional behaviour
This definition states that a person is clearly not functioning correctly and is therefore not leading what would be considered a 'normal' life. He or she may lack the full range of emotions or feelings and may participate in only a limited range of behaviours that does not allow for a fully functioning lifestyle.

Personal distress
We all suffer from some form of distress but sometimes distress may be indicative of an underlying psychological problem. Distress therefore becomes the symptom of psychological disorder and is often used as a way of gauging someone's mental state.

Observer discomfort
People whose behaviour causes other people to regularly feel uncomfortable are often seen as suffering from a psychological disorder. Their behaviour is often very disruptive and destructive to other people around them.

Unpredictable behaviour
If behaviour is inappropriate to a situation it can often be seen as being unexpected and unpredictable. This can include such behaviours as over-reaction and being over or under-concerned and is often associated with high or low levels of emotion.

Irrational behaviour
If behaviour does not make sense to others and this behaviour cannot be reasonably explained or verbalised by a person, then it may be seen as a form of abnormal behaviour or as signs of a mental disorder. The main aspect of this definition is the belief that all behaviours should in some way be explained through a rational reason for their existence.

Deviation from ideal mental health
Psychologists often consider certain criteria to be indicative of someone who is not suffering from a mental disorder. If these criteria are not met then people and their behaviour will be seen as suffering from a mental disorder.

These 6 criteria are:

  1. Positive view of self: self awareness, self esteem, self acceptance
  2. Personal growth and development: developing talents and abilities to their full potential
  3. Autonomy: being capable of independent action
  4. Accurate view of reality: not distorting the world in any way
  5. Positive friendships: the ability to build relationships of many varieties
  6. Environmental mastery: meeting the requirements of the many different situations encountered in everyday life

Key considerations in defining abnormality

This varies across societies, countries and continents. Each culture has its own ideas of what will be considered abnormal and normal behaviour. The full extension of this concept leads us to suggest that what is seen as a mental disorder in one society is not seen as a mental disorder in another. Therefore, it cannot be stated that one society is superior to another in defining mental illness, or that one society has a lower occurrence of mental disorders than another. Everything is relative to the prevailing culture within whose influence we move.

Cultures vary between each other and within each other. There are often sub-cultures (a culture within a culture). What may seem normal today may have been seen as unacceptable in the past and may be frowned upon in the future. Social norms are not fixed and will inevitably change over time.

Resource Descriptions

Guided Tour
Scene  Rich Media