Abnormality [AO1 and AO3]

1. Statistical infrequency

Abnormality is behaviour which is very rare.

• Doesn't distinguish between desirable and undesirable behaviour

For example, it is rare to have an IQ over 150, but this is desirable. Equally, some common behaviours are undesirable - like depression, which is not rare and is not desirable. Using statistical infrequency to define abnormal behaviour means that we are unable to distinguish between desirable and undesirable abnormality. 

• Cut-off point is subjectively determined 
  

For abnormality to be defined in terms of statistical infrequency, there must be a point which separates normality from abnormality. Someone might decide that - for example - abnormal sleep is, "sleeping for fewer hours than 80% of the population," but someone else might argue than 90% is a better cut-off point. 

2. Deviation from social norms

Society has unwritten rules about how to behave - for example, being fully clothed in public, or politeness. Abnormality is when someone behaves differently to these rules.

• Times change

Social norms vary as times change. What is socially acceptable now may not have been acceptable 50 years ago. For example , homosexuality is acceptable today but in the past it was included under "sexual and gender indentity disorders" in the DSM. This definition allows mental health professionals to define individuals who go against social attitudes as mentally ill. Thomas Szasz claimed that the concept on mental illness was simply a way to exclude non-conformists from society. 

• Related to context

A person on a beach wearing next to nothing is regarded as normal, but the same outfit at a formal gathering would be seen as abnormal. Social deviance on its own can't offer a complete…