What is clinical psychology?Clinical psychology is about the study of mental health and mental disorders. This application of psychology focuses on diagnosing, explaining and treating mental illness.
3.2 Definitions of abnormality
Normality and abnormality
It has been hard to describe exactly what is meant by ‘abnormal’ for a number of reasons. First of all, there is no clear definition of what is ‘normal’ making it difficult to identify what is not normal.
Also, there is no one shared characteristic between everything that is described as abnormal, making it difficult to operationalise. Different cultures also interpret behaviours differently, so whereas Westernised countries may see something as abnormal, others may see this as perfectly normal, but you will come across cultural issues later on.
Therefore, there are a range of definitions of abnormality used by different psychologists. There are two discussed in detail as part of this application, and two others (‘abnormality as dysfunction and distress’ and ‘deviation from ideal mental health’) may also be looked at for evaluative purposes.
Deviation from statistical norms
Under this definition of abnormality, a person’s trait, thinking or behaviour is classified as abnormal if it is rare or statistically infrequent. What is regarded as statistically unusual all depends on normal distribution. A distribution curve can be drawn to show what proportions of people share the traits, characteristics or behaviours in question.
Anything further than two standard deviations is said to be statistically infrequent. Therefore, a very small subset of the population (2.2% in total) have an IQ which is more than two standard deviations from the statistical norm, and are said to have an abnormally low IQ (this means less than 70). Similarly, anyone with an IQ above 130 is said to have an abnormal IQ score, and these people site within the 2.2% above 2 standard deviations from the mean. Normal distributions are calculated by mathematicians based on formulae which are designed to give standard distributions.
A normal distribution curve has 95.4% of scores either side of the mean which are within two standard deviations, and since this is a high percentage, it is considered statistically frequent. The more a person deviates from that mean, the more they are considered to be abnormal, although anyone within that centre 95.4% is considered to be normal. Anyone outside that percentage group is considered to be abnormal, approximately 2.2% at either end.
The statistical definition gives a quantitative measure which is objective, and is more likely to be reliable because the scores come from tests or studies which can be repeated.
Some measures of abnormality under this definition highlight ‘a lack of normal functioning’ and therefore this is a scientific measure of whether or not someone is entitled to assistance, support and funding.
What is considered abnormal from a statistical sense may actually not be undesirable, for example people within the top 2.2% of the population with high IQs (above 130) are considered abnormal, but this is actually seen as a good…