One way of defining abnormality is in terms of characteristics or
behaviours that are statistically infrequent (the deviation from
statistical norms definition). However, this does not take into
account the desirability of a characteristic or behaviour. The
definition also fails to recognise that in all cultures large numbers
of people may engage in behaviours that constitute mental disorders. A
further problem is the failure to identify how far a person must
deviate before being ‘abnormal’. Such decisions are difficult to make
and then consequently justify.
The deviation from ideal mental health definition proposes that
abnormal people do not possess characteristics that mental healthy
people do, or possess characteristics that mentally healthy people do
This particular definition relies on value judgements about what
constitutes ideal mental health. It is also bound by culture,
era-dependent, and limited by the context in which behaviour occurs.
Abnormality has also been defined as a failure to function adequately
(by not achieving some sense of personal well-being and making some
contribution to a larger social group). Experiencing personal distress
or discomfort, causing distress to others, and behaving in an
unexpected or bizarre manner are often the reasons why people come to
the attention of psychologists. Many consider the failure to function
adequately definition as being the most useful single approach, and
the one closest to common sense. However, none of the above on its own
constitutes an adequate definition of abnormality, since bizarre
behaviour, for example, might actually allow a person to function
adequately in a particular context.
Another way of defining abnormality is in terms of a deviation from
social norms. Abnormality is seen as behaving in ways society
disapproves of, or not behaving in ways it approves of. Like other
definitions, this one is bound by culture and era-dependency. Also,
since most people have behaved in ways society disapproves of, most
would be defined as ‘abnormal.’
No one definition on its own is adequate. Behaviours that are
classified as mental disorders do not necessarily reflect all of the
various definitions. A truly adequate definition can probably only be
achieved through a multiple definitions approach.
Psychologists disagree about the causes of abnormality and the best
way in which to treat them. As a result, four different models of
abnormality were devised in order to cover all of the different
theories. One such model is the biological model which regards
abnormality of mental functioning as an illness or a...