• Deviation from social norms
• Failure to function adequately
• Deviation from ideal mental health
• Deviation from the statistical norm
Deviation from social norms:
Social norms are acceptable or expected patterns of behaviour. According to this definition, abnormality is deviation or violation of acceptable patterns of behaviour or social norms. For example it is not acceptable to say you hear voices in your head (schizophrenia). It is not a social norm to starve yourself to death (anorexia). Social norms can be explicit (clearly set down in society such as laws) or implicit (common expectations of behaviour).
Deviation from social norms doesn’t always result in psychological abnormality. Such behaviours may be classed as eccentric rather than abnormal in a pathological sense for example streaking across sports pitches could be classed as eccentric but we wouldn’t assume the person is mentally unstable. However if somebody walked down the street talking out loud to an invisible person we may suspect they have a mental disorder.
There are people who violate legal norms, however rather than being considered to have a psychological disorder they are labelled as criminals. However with certain types of criminal behaviour, e.g. rape or mass murder, it is difficult to accept that anybody normal could have carried out such behaviour.
Failure to function adequately:
According to this definition, failure to function adequately means that a person is unable to live a normal life, e.g. got to work, form close relationships, or perhaps venture outdoors. When particular behaviour interferes with everyday life then it might be regarded as abnormal.
This is not a true definition of abnormality, but a way of determining the extent of someone’s problems and the likelihood that they might need professional help. But may not be dysfunction alone that encompasses abnormality e.g. some people starve themselves in protest.