Diagnosis in Psychiatry

DR A J MANDER

CONSULTANT PSYCHIATRIST

Structure of Seminar (1)

◼ Using depression as an example:-

a) Diagnosis & terminology

b) Role of DSMIV (and ICD-10 and clinical diagnosis)

c) Capacity for work and diagnosis

d) Longitudinal course (episodic or lifelong)

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Structure of Seminar (2)

◼ If time permits:-

a) PTSD and implications of delayed onset

b) Somatoform disorders

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Diagnosis & Terminology (1)

a) Diagnoses are simply concepts

b) Most psychiatric disorders should be assumed to involve cerebral pathology of some kind

c) Classification should be based on aetiology where possible

d) Aetiology of most psychiatric conditions is still unknown leading to a reliance on clinical symptoms

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Diagnosis & Terminology (2)

a) Clinical interview identifies symptoms

b) The mental state examination is focussed on observable signs

c) Collateral information

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Diagnosis & Terminology (3)

a) Identified pattern leads to clinical diagnosis

b) US/UK diagnostic project (1972)

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Diagnosis & Terminology (4)

a) DSMIV and SCID - operational definitions

b) ICD-10

i) Diagnostic guidelines for clinical diagnosis (“The Blue Book”)

ii) Diagnostic criteria for research (“The Green Book”)

c) Right versus useful

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Diagnosis & Terminology (5)

◼ The following is taken from the introduction to DSMIV:-

In DSMIV, there is no assumption that each category of mental disorder is a complete discrete entity with absolute boundaries dividing it from other mental disorders or from no mental disorder.

THERE IS NO ASSUMPTION THAT ALL INDIVIDUALS DESCRIBED AS HAVING THE SAME MENTAL DISORDER ARE ALL ALIKE

IN ALL IMPORTANT WAYS

The clinician using DSMIV should therefore consider that individuals sharing a diagnosis are likely to be heterogeneous even in regard to the defining features of the diagnosis and that boundary cases will be difficult to diagnose in all but a probabilistic fashion.

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Diagnosis & Terminology (6)

◼ “USE OF CLINICAL JUDGEMENT”

DSMIV is a classification of mental disorders that was developed for use in clinical, educational and research settings. The diagnostic categories, criteria and contextual descriptors are meant to be employed by individuals with appropriate clinical training and experience in diagnosis. It is important that DSMIV not be applied mechanically by untrained individuals.

THE SPECIFIC DIAGNOSTIC CRITERIA INCLUDED IN DSMIV ARE MEANT TO SERVE AS GUIDELINES TO BE INFORMED BY CLINICAL JUDGEMENT AND ARE NOT

MEANT TO BE USED IN A COOK BOOK FASHION

For example, the exercise of clinical judgement may justify giving a certain diagnosis to an individual even though the clinical presentation falls just short of meeting the full criteria for the diagnosis as long as the symptoms that are present are persistent and severe. On the other hand, lack of familiarity with DSMIV or the use of excessively flexible and idiosyncratic application of DSMIV criteria or conventions substantially reduces its utility as a common language for communication.

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Diagnosis & Terminology (7)

◼ “USE OF DSMIV IN FORENSIC SETTINGS”

When the DSMIV, categories, criteria and contextual descriptions are employed for forensic purposes, there are significant risks that diagnostic information will be misused or misunderstood. These dangers arise because of the imperfect fit between the questions of ultimate concern to the law and the information contained in a clinical diagnosis. In most situations, the clinical diagnosis of the DSMIV mental disorder is not sufficient to establish the existence for legal purposes of a “mental disorder”, “mental disability”, “mental disease” or “mental defect”.

In determining whether an individual meets a specific legal standard (egfor competence, criminal responsibility or disability), additional information is usually required beyond that contained in the DSMIV diagnosis. This might include information about the individual’s functional impairments and how these impairments affect the particular abilities in question.

IT IS PRECISELY BECAUSE IMPAIRMENT, ABILITIES AND DISABILITIES VARY WIDELY WITHIN EACH DIAGNOSTIC

CATEGORY THAT ASSIGNMENT OF A PARTICULAR DIAGNOSIS DOES NOT IMPLY A SPECIFIC LEVEL OF

IMPAIRMENT OR DISABILITY

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Capacity for Work &

Relationship to Diagnosis

◼ It follows that there is no specific link between diagnosis and capacity for work which is a function of symptom type (such as organisation, concentration, energy level, motivation, reality testing etc), and severity.

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Episodic versus Longitudinal 11

a) A longitudinal view is most appropriate. Depending on condition approximately one third of patients have one episode of illness and the risk of further episodes is a function of many factors including the number of previous episodes.

b) The issues of recurrence, aggravation or exacerbation is considered on a case by case basis.

c) As a rule of thumb, if six months has passed symptom free and without active treatment, then a further episode would be deemed to be

a new episode.

The Challenge 12

Major

Depression

Generalised

AnxietyPTSD

Depressed Mood P X P

Diminished Interest P P P

Weight Loss P P P

Sleep Disturbance P P P

Agitation P P P

Fatigue P P P

Feelings of Worthlessness P X P

Poor Concentration P P P

Thoughts of Death P X P

PTSD

◼ There is specific recognition clinically, in DSMIV, and in ICD-10 that delayed onset occurs.

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Somatoform Disorders

◼ This group of disorders include hysterical and hypochondriacal syndromes as well as a group of other related disorders where symptoms are produced without adequate physical cause and includes:

a) Somatisation disorderb) Conversion disorderc) Pain disorderd) Hypochondriase) Body dysmorphic disorder

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Somatisation Disorders

◼ A pattern of recurring, multiple, clinically significant somatic complaints. According to DSMIV, these must have begun before age 30 and must include at a minimum; pain in at least four sites, two gastrointestinal symptoms, one sexual symptom and a pseudoneurologicalsymptom.

THE UNEXPLAINED SYMPTOMS

ARE NOT INTENTIONALLY

FEIGNED OR PRODUCED

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