Mental health articles

Systems for classifying mental disorder or ‘illness’ stem from the medical model, which as Tyrer and Steinberg (1998) point out is not an aetiological model itself but an approach to diagnosing individual disorder. In a general sense all models apply this process, with exception perhaps of the social model, although the systems that are used for classification purposes vary between models. For example, when discussing the cognitive model we described Ellis’s ABC framework for defining specific cognitive problems that arise between an activating event and the behavioural or cognitive consequence.

Problem-oriented statements can be constructed from such an analysis, which represent one approach to classification. For example, ‘When I make eye contact with strangers in public (Activating event), I believe they immediately think bad of me (Belief), and therefore I avoid social interaction (Consequence).’ This statement classifies a cognitive or behavioural problem depending on your perspective. Medical diagnosis is another classification system, which represents the dominant frame of reference for most mental health workers internationally. These diagnoses are described in two classification systems; the International Classification of Disease (ICD-10 World Health Organization; and the Diagnostic and Statistical Manual for Mental Disorders. In the UK our primary frame of reference is ICD-10, which is described below. But first we draw out some differences between the two systems.

Ideally each diagnosis should be mutually exclusive and stand independently of other symptoms associated with other diagnoses. Rarely in practice is this achieved. More often than not a range of symptoms may indicate the relevance of two or more diagnoses. This point is particularly pertinent to the ICD-10 classification system, which uses a single axis upon which to select diagnoses for an individual’s disorder. If more than one is selected they may appear to contradict each other. However, psychiatric diagnoses are based on a hierarchical system so that each disorder can manifest symptoms present in disorders lower down the hierarchy, but not above it. For example, an individual who experiences persistent low mood may receive a diagnosis of depression. However, if the low mood is accompanied by delusional thought patterns, a diagnosis of schizoaffective disorder will take precedence over a diagnosis of depression. In contrast to the single-axis approach of ICD-10 there is an increasing tendency to use multi-axial approaches in which clinical diagnosis is only one part.

Thus, in DSM-IV the clinical diagnosis is axis 1, personality status is described in axis 2, and developmental delay, intellectual status, physical health, social functioning and reactions to stress are all separate axes. This approach allows several descriptors to be attributed to an individual’s symptoms and their general condition. Before examining ICD-10 diagnostic categories it is important to stress that any classification system classifies syndromes and conditions, but not individuals. We may all suffer from one or more disorders of either a mental or physical nature at different times in our lives. It is meaningless, therefore, as well as stigmatizing, to use such labels to describe people. A person should never be equated with a disorder, physical or mental.

Tags: classification, disorder, mental, mental disorder