Classification of disorders - DSM, why we classify and the impact that classification has.
Clinical Psychology: Classification of disorders
Why classify disorders?
In simple terms clinical psychology is the application of scientific methods to understand and resolves human problems. Classification helps us to do this, and enforces some homogeneity upon the groups that we investigate. This allows us to develop theories of how disorders develop, which in turn informs us about how these disorders might be treated. Without some agreement about what constitutes a particular disorder, we would not be able to unearth common underlying processes (as it would be a heterogeneous group of people), and we would be unable to communicate with other scientists and health professionals about the theories we develop.
How should we classify?
A good classification system needs to do a number of things, such as:
 Divide into mutually exclusive and collectively exhaustive subclasses: Disorders should be distinct (i.e., if something belongs to one subclass it cannot belong to another) and collectively exhaustive.
 Necessary & sufficient conditions: there must be characteristics that are necessary for classification into a subclass and there must also be a set of sufficient conditions to belong to a subclass.
 Concept: once the conditions of membership have been defined, the subclass must be ...