One definition of abnormality is deviation from social norms. This refers to behaviour that deviates from the societal expectations of the culture the subject is part of. Examples of British social norms include behaviours like politeness and reserve. The main difficulty with this concept is that social norms change rapidly, so something that seems socially acceptable now may not have been socially acceptable a few years past. A second issue is how deviance is judges by context and degree. For instance someone who wears unusual clothing during their leisure time is unlikely to be considered psychologically abnormal also much as socially eccentric.
A second definition is failure to function adequately. This refers to how a person’s alleged abnormality affects their ability to go about day-to-day existence. For example, someone with an eating disorder could be considered psychologically abnormal because it impedes their natural survival instinct to eat. One of the biggest problems with this definition is the question of who judges what does and does not affect a person’s ability to ‘function adequately’. Secondly there is the issue of how the definition of ‘functioning adequately’ can be applied cross-culturally. For instance someone from another culture may exhibit a behaviour which is consistent with this definition of abnormality in western culture, but would be perfectly normal in their own culture.
The final definition is that of deviation from ideal mental health. Marie Jahoda (1958) laid down six criteria from ideal mental health and said that the absence of these criteria indicates abnormality and potential mental disorder. The biggest issue with this definition is the criteria, specifically in that very few people fulfil them all and therefore suggesting that the vast majority of people are abnormal. Secondly, Jahoda’s theory relies on being able to diagnose