Current Classification Systems

Question 1

What are the two major classification systems used in the field of psychotherapy?

Answer 1

1. ‘The International Classification System for Diseases’ (ICD)
2. ‘The Diagnostic and Statistical Manual of Mental Disorders’ (DSM)

Question 2

What are the explicit operational criteria for diagnosis introduced by both classification systems?

Answer 2

• There is a specified list of symptoms
• All of which must be present
• For a specified period of time
• In relation to age and gender
• Stipulation as to what other diagnoses mustn’t be present

Question 3

ICD

Answer 3

• The ICD is published by the World Health Organisation (WHO).
• It facilitates the collection of general health statistics.
• Only one of its 21 chapters (chapter 5) is devoted to psychiatry.
• Mental health disorders were not included until its 6th revision in 1952.
• Currently on its 10th edition it is an international document and it is available in most languages.
• Chapter 5 is divided into 10 main categories:

1. Organic disorders, e.g., dementia
2. Substance abuse, e.g., alcoholism
3. Schizotypal disorders, e.g., schizophrenia
4. Affective disorders, e.g., depression
5. Neurotic disorders, e.g., anxiety
6. Behavioural syndromes affected with physical factors, e.g., anorexia
7. Disorders of adult personality, e.g., paranoid personality disorder
8. Mental retardation
9. Psychological development, e.g., autism
10. Behavioural disorders with onset in childhood, e.g., conduct disorders.

Question 4

DSM

Answer 4

• The DSM was developed in America and is only available in the English language.
• Despite this, it is more widely used than the ICD.
• It is the APA’s official classification system, currently on its 5th edition.
• The DSM (but not the ICD) is multi-axial; clinicians have to assess the patients in five different axes (areas of information) before making a diagnosis. The inclusion of the axes reflects the assumption that most disorders are caused by the interaction of biological, sociological and psychological factors.
• The patient is assessed more broadly, giving a more global depth in picture.
• The DSM (but not the ICD) includes the personal and social consequences of the disorder.
• DSM-V - The five axes:

1. Axis I – Clinical disorders (e.g., depression, schizophrenia).
   Axis II – Personality disorders and intellectual disabilities.
   Axis III – Medical conditions affecting mental health (e.g., brain injury).
   Axis IV – Psychosocial and environmental problems (e.g., unemployment).
   Axis V – Global Assessment of Functioning (GAF) score (overall level of functioning).
2. Axis I - Clinical disorders, e.g., depression, schizophrenia.
3. Axis II - Personality disorders and intellectual disabilities.
4. Axis III - Medical conditions affecting mental health, e.g., brain injury.
5. Axis IV - Psychosocial and environmental problems, e.g., unemployment.
6. Axis V - Global Assessment of Functioning (GAF) score (overall level of functioning.

Question 5

Characteristics of an Ideal Diagnostic System

Answer 5

1. Features of a disorder must be present of absent (category description should aid this decision).
2. Categories should be jointly exhaustive (nothing is left out).
3. Categories should be mutually exclusive (shouldn’t overlap).
4. In other words, the system should be valid and reliable.

Question 6

Reliability of Diagnostic Systems

Answer 6

Reliability in this context means that each time the classification system is used for a particular set of symptoms, it should produce the same outcome. The consistency with which clinicians agree on a diagnosis is known as inter-rater reliability.

Question 7

Validity of Diagnostic Systems

Answer 7

Validity is concerned with the appropriateness of the classification categories; whether the system puts together the people whose symptoms come from the same causal factors and who respond to similar treatments.

1. Descriptive validity is the extent to which the diagnostic classification provides significant information about the individuals placed in the category.
2. Predictive validity is the extent to which a diagnosis is able to predict the course of the disorder and the efficacy of different types of treatments.

Question 8

Reliability and Validity of DSM

Answer 8

The early editions of the DSM had huge problems with reliability meaning clinicians could not agree on diagnoses. The current version is considerably improved based on extensive research but there are still many problems.

Similarly, although levels of validity have improved, some still think that certain categories lack validity. For example, issues of co-morbidity or some individuals not fitting in any category at all raises questions about validity. Possible gender and culture bias also raise issues of validity.