Definitions of abnormality: statistical infrequency - Psychopathology

Definitions of Abnormality:

THE STATISTICAL DEFINITION: 

Under this definition, any behaviour and characteristic that occurs rarely in relation to the rest of the population, is considered ‘abnormal’ (usually when it deviates ± 2sd away from the statistically calculated average). It has a mathematical basis, worked around the ‘normal distribution’ – in which most people’s behaviour (the ‘norm’) will cluster around the middle.

For example, the average IQ score is 100, and only 2% of the entire population have a score of 70 or below – this definition would therefore see these individuals as ‘abnormal’ and they would be liable to receive a diagnosis of a psychological disorder (intellectual disability disorder).

Evaluations:

1.     Some mental disorders, like phobias (an anxiety disorder), aren't statistically rare enough to be classed as 'abnormal', and so those who suffer from phobias to an extreme level, aren't regarded as having a problem. This means that, according to this definition, those who have extreme, irrational fears, are not 'abnormal' and hereby would not receive the treatment they need.

2.     Some statistically infrequent behaviours - like having a very high IQ - may be desirable characteristics, yet under this definition they are viewed as 'abnormal' which would therefore lead to a misdiagnosis. Therefore, suggesting that the statistical infrequency definition is not always accurate in defining abnormality.

3.     When someone is living a happy and fulfilled life, there is no benefit to them being labeled as ‘abnormal’, regardless of how unusual they may appear. Someone with a very low IQ but who is not distressed and quite capable of working (ect) would simply not need the label of having a ‘disability’ or being ‘abnormal’ – this may just have a negative effect on the way others view them and the way they view themselves (leading to a self-fulfilling prophecy).

4.     The mathematical nature of this definition means that it is clear what is defined as abnormal and what is not. There is no opinion involved and it provides a quantitative measure of abnormality, which means that it is objective, and therefore more likely to be reliable and consistent with the findings.

5.     It also holds some real-life applications: due to the mathematical basis of it, it makes it a more scientific approach and therefore it can be used as a diagnostic tool for the clinical assessment of a patient.