Diagnosis & Classification of Mental Disorders

Diagnosis: Mental disorders

Considerations when assessing psychiatric symptoms:

– Is there a mental illness and if so what is it?

Diagnosis: Mental disorders

‘mental disorder’?– Abnormalities of mood, emotion, cognition,

behaviour – Signs and symptoms are on continuum,

there’s no clear division between health and illness

– Manifestations vary age, gender, race

Diagnosis: Mental disorders

– Threshold for illness/disorder set by convention

– diagnosis linked to the definition of mental illness

– difficult to define and operationalise

Diagnosis: Mental disorders

No definitive lesion, laboratory test or abnormality of the brain tissues

Dependent on patient & family reports of intensity and duration of symptoms

Signs from clinician’s mental state assessment and observation of behaviour

Diagnosis: Mental disorders

These cues are grouped together by the clinician into recognisable patterns or syndromes

When a syndrome meets all the criteria for a diagnosis, it constitutes a mental disorder

Diagnosis: Mental disorders

Manifestations of mental disorders do not fall into distinct categories

Categories are broad and overlapping

Any particular patient may manifest symptoms from more than one category

Diagnosis: Mental disorders

Mental illness is heterogeneous- ever changing and difficult to characterise

Current psychiatric classifications are imprecise requiring a constellation of clinical features to define them

Diagnostic reliability

Diagnostic reliability challenged in 1960s – psychiatrist (Szasz 1960/1) plus classic study Rosenhan (1973)

Several studies showed low diagnostic reliability

The reliability of psychiatric diagnosis was limited by the lack of widely accepted and standardized diagnostic criteria

The DSM (APA) and ICD (WHO) were developed to achieved greater objectivity, diagnostic precision and reliability

Diagnostic and Statistical Manual of Mental Disorders (DSM)

DSM 1 – 1952, DSM 11 -1968 Symptoms were not specified for specific

disorders Causes were associated with subconscious

conflicts or maladaptive reactions to life problems

Focus was the differentiation of neurosis and psychosis

DSM

DSM 111 (1980) – Focus how to identify psychiatric disorders in clinical practice on the basis of psychopathology

DSM III-R (1987), DSM-IV (1994), DSM-IV-R (2000)

DSM –V (2013)

Structure of DSM-IV

The DSM-IV organizes each psychiatric diagnosis into five levels (axes) – Axis I: clinical disorders, including major

mental disorders, as well as developmental and learning disorders

– – Axis II: underlying pervasive or personality

conditions, as well as mental retardation

Structure of DSM-IV

– Axis III: Acute medical conditions and Physical disorders.

– Axis IV: psychosocial and environmental factors contributing to the disorder

– Axis V: Global assessment of functioning

Structure of DSM-IV

Axis 1 organises mental disorders into 16 major diagnostic classes

For each disorder a specific criteria is set out for making the diagnosis

Structure of DSM-IV

For most disorders symptoms must be sufficient to cause

– “clinically significant distress or impairment in social, occupational, or other important areas of functioning“

DSM- 5

International Classification of Diseases (ICD)

ICD-10 came into use in WHO Member States 1994.

This is the latest in a series which has its origins in the 1850s.

ICD-10

Since the 1990s, the APA and WHO have worked to bring the DSM and the relevant sections of ICD into concordance, but some differences remain

Critique of DSM

Compilation exclusively by US psychiatrists

Continuing debate about validity and reliability

Relationship of DSM authors with drug companies

Critique of DSM

increase in categories driven by financial incentives – capitalise on a best seller

Increased medicalization of normal

behaviour

DSM perpetuating the deficiencies of previous classifications – not working towards a more scientific system

Consclusion

Diagnosis rests on clinician judgement about whether symptoms and impairment of functioning meets diagnostic criteria

Cultural/Class differences in emotional expression and social behaviour can be misinterpreted as impairment

Clinicians must be sensitive to the context and meaning of exhibited symptoms