Many definitions have been used to define psychological disorders. However, most of the definitions have 4 common features i.e. deviance, distress, dysfunction and danger. In other words, psychological disorders are deviant (different, bizarre, unusual and extreme), distressing (unpleasant and upsetting to the individual and also to others), dysfunctional (interfering with the individual’s capability to carry out life activities in a proper manner) and possibly dangerous (to the person and to others).
The following is a brief historical account of how psychological disorders are viewed over the ages.