Chapter 3Classification and Diagnosis

INTRODUCTION TO CLINICAL PSYCHOLOGY 2EHUNSLEY & LEE

PREPARED BY DR. CATHY CHOVAZ, KING’S COLLEGE, UWO

Introduction – Topics

Important Aspects of a Classification Scheme

Defining Abnormal Behaviour Diagnosis and Defining Disorder The Development of a Disorder The DSM Approach to Diagnosis: History The DSM Approach to Diagnosis The DSM Approach to Diagnosis

Problems/Limitations Other Classification Schemes

Classification: a way for scientists to organize, describe, and relate the subject matter of their discipline

Validity: whether a classification scheme is accurately capturing reality

Utility: how useful a classification scheme is

Diagnosis system: a classification based on rules used to organize and understand diseases and disorders

Important Aspects of a Classification Scheme

Categorical approach: an object is determined to be a member of a category or not (e.g., depressed or not depressed)

Dimensional approach: an object differs in degree from others – a continuum (e.g., mildly depressed, moderately depressed, severely depressed)

Prototype model: members of a category may differ in degree to which they represent a common example (used in DSM)

Important Aspects of a Classification Scheme

What is abnormal? Many factors need to be considered including: The cultural and societal context Whether there is distress or discomfort Whether the problem is harming others How common the problem is How much it is interfering with a person’s ability

to function If it is common for that person’s developmental

stage (developmental psychopathology)

Defining Abnormal Behaviour

No diagnosis is based on a single symptom DSM-IV-TR defines disorder in a complicated

fashion including Symptoms associated with distress or

impairment/disability Increased risk of suffering Culturally atypical Not just deviant behaviour (unless there is also

dysfunction)

Diagnosis and Defining Disorder

Wakefield – Harmful Dysfunction: the problem must be clear and there must be harm to person or others

Dyscontrol: impairment must be involuntary or not readily controlled

Diagnosis and Defining Disorder

Most all contemporary models are biopsychosocial – but different theories represent different emphases

Some models emphasize biological aspects while others emphasize psychological or social aspects

Life stress model – important impact of the number of life stressors on the development of disorders

The Development of Disorders

First edition of DSM (1952) had fairly vague terms and emphasized psychodynamic contributions

DSM-II (1968) was less psychodynamically focused as medications were more commonly being used

DSM-III (1980) guided by Robert Spitzer, was atheoretical (revision done in 1987)

Focus on diagnostic criteria, multiaxial, increase in focus on reliability

The DSM Approach to Diagnosis: History

DSM-IV (1994) Further focus on reliability ‘Work groups’ worked on clusters of disorders Text revision (diagnostic criteria unchanged) DSM-

IV’TR’ completed in 2000

DSM-V planned for 2012

The DSM Approach to Diagnosis: History

The DSM-IV uses a multiaxial classification approach. Axis I and II are the mental disorders and III-V provide the medical and psychosocial contexts

The DSM Approach to Diagnosis: History

Axis I: Clinical Disorders and Other Conditions That May Be a Focus of Clinical Attention All the mental disorders in the DSM-IV except for

Personality Disorders and Mental Retardation. Multiple disorders can exist on Axis I

Axis II: Personality Disorder and Mental Retardation These were placed on another axis so that they

were not overlooked

The DSM Approach to Diagnosis

Axis III: General Medical Conditions Current medical conditions that may be relevant to

the understanding or treatment of Axis I or II

Axis IV: Psychosocial/Environmental Problems Psychosocial and environmental information that

may influence the diagnosis, treatment, and prognosis of Axis I or II, including educational, economic, housing, legal problems, etc.

Axis V: Global Assessment of Functioning Score of 1-100 indicating their functioning level

The DSM Approach to Diagnosis

Importance of considering culture Information in the text on cultural variation Cultural bound syndromes Diagnosis should not occur if symptoms are

culturally typical Diagnosis must be done in a culturally sensitive

context

The DSM Approach to Diagnosis

Comorbidity: when a person receives two diagnoses at once DSM attempts to decrease the likelihood of this

with several exclusionary rules However, comorbidity is very common in the DSM

(often >40%)

Diagnoses do not account for normal reactions to life stressors (e.g., divorce, terminal illness)

The DSM Approach to Diagnosis Problems/Limitations

Diagnostic criteria seem to include too much of the population (sometimes 25-30% of the population)

Although better than the earlier versions DSM diagnoses are not as reliable as hoped

Heterogeneity of symptom profiles is problematic

Many of the subtypes and features of a disorder are not based on empirical data

The DSM Approach to Diagnosis Problems/Limitations

Validity of some disorders is questionable (i.e., that the diagnosis is a discrete entity)

Current research indicates that some disorders may be both a category and a continuum (e.g., depression)

Resilience is often not included in understanding disorders, yet is a common aspect of human functioning

The DSM Approach to Diagnosis Problems/Limitations

International Statistical Classification of Diseases and Related Health Problems (ICD-10) – developed by World Health Org. Mental and behavioural disorders subsection

(compatible with the DSM-IV) Companion “International Classification of

Functioning, Disability and Health (ICF)” focused on overall functioning and health

Achenbach System of Empirically Based Assessment

(ASEBA)– internalizing/externalizing problems

Other Classification Schemes

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