Classification of Psychiatric Disorders

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Classification-
The process by which the complexity of phenomena is reduced by arranging them into categories according to some established criteria for one or more purposes.

A disorder-
An assumption is that a psychiatric disorder is any emotion, thought, or behavior that is "abnormal."

Normalcy and Abnormality

Normalcy or what is considered abnormal varies widely and depends on the patient's or (clinician's):

Ethnic or cultural background,
Religious or moral values,
Upbringing, and
Age or generational cohort.

DSM-IV-TR definition of disorders:
As syndromes of symptoms or behaviors associated with distress or disability or with a significant increase risk of suffering, death, pain, disability, or an important loss of freedom.

Symptoms- are the patient's subjective experience and may include thoughts, feelings, behavior, and physical sensations.
Signs- are the clinician's objective observations of the patient.

Note: In psychiatry, no behavioral symptom or mental status finding is pathognomonic for one specific diagnosis. For example, auditory hallucination can be seen in schizophrenia, mania, severe depression with psychotic features, cocaine or stimulant intoxication, vascular dementia, or even severe borderline personality disorder.

Classification of mental disorders consists of specific mental disorders that are grouped into various classes on the basis of some shared phenomenological characteristics. Ideally, a classification of disorders is based on knowledge of aetiology or pathophysiology.

Neuroscientists have not yet produced sufficient data to design a diagnostic system that relies on biomarkers that enable psychiatric diagnoses to be based on causes rather than symptoms.

Instead, diagnosis of mental disorders is based on clinical observations of clusters of signs and symptoms that are grouped together into disorders or syndromes. These classifications are then agreed upon by a consensus of psychiatrists and other mental health professionals.

Organic Disorders-
Arise from demonstrable cerebral or systemic pathological processes, e.g., Dementia, delirium, and various neuropsychiatric syndromes.

Functional-
Is an umbrella or default term for all other psychiatric disorders. The implication of organic/functional classification:

Functional disorders have no biological basis, while psychological and social factors are irrelevant for organic disorders—this is not true.
Practical implication: Organic defines disorders aetiologically, whereas all other psychiatric disorders are purely descriptive and are based on clusters of symptoms and signs.

Note: The organic-functional dichotomy is neither valid nor helpful and should be abandoned.

The concepts were important in most systems of classification in the past.
Neither is used as an organizing principle in ICD-10 or DSM-V, but in everyday clinical practice, these terms are still useful as general descriptors.

Psychosis:

Term unsatisfactory, has lost its classificatory eminences.
A convenient term for disorders that are usually severe, with delusions, hallucinations, or unusual or bizarre behavior, especially when a more precise diagnosis cannot yet be made.

Neurosis:

Has been removed from the organizing principles of current classification.
More information can be conveyed using more specific and descriptive diagnoses, e.g., anxiety disorder.
The term is still used as descriptors to indicate disorders that are often comparatively mild and usually associated with some form of anxiety or marked tension, especially if the specific disorder cannot yet be determined.

Applies to schemes of classifications in which 2 or more separate sets of information (e.g., symptoms, etiology, and personality type) are coded.

Was first proposed by Essen-Moller and is now an integral part of DSM-IV & V, available within ICD-10.

Hierarchies of Diagnosis

If two or more disorders are present, it is conventional to assume that one takes precedence and is regarded as the main disorder for the purposes of treatment and recording. For example, an organic disorder takes precedence over schizophrenia, and schizophrenia over mood disorder.

There is some clinical evidence for an inbuilt hierarchy of significance between disorders. For instance, anxiety symptoms commonly occur with depressive disorders and are sometimes the presenting features. Anxiety may receive little response, but if the depressive disorder is treated, there is improvement in anxiety as well as depressive symptoms.

It encourages the clinician to focus on all the various disorders that may be present and not assume that the disorder highest in the hierarchy is necessarily the only or even the most important target for treatment.

Diagnostic "rule" used in the current classificatory system, especially in DSM-V, encourages multiple diagnoses.

Co-morbidity (Dual Diagnosis)

Less emphasis is now placed on hierarchies of diagnosis, but greater weight is now placed on co-morbidity.
For the following reasons:

Research has shown that co-morbidity is very common. For example, 50% of patients with major depressive disorder also meet criteria for an anxiety disorder.
Co-morbidity covers two different circumstances:

Disorders that are currently considered distinct but are probably causally related, i.e., one disease process but two or more clinical manifestations, which are currently diagnosed separately due to lack of knowledge or because of clinical convention. Example: Depressive disorder and anxiety disorder.
Disorders that are causally unrelated, i.e., the chance of co-occurrence of two disorders is unlikely. Example: Pre-senile dementia in a person with long-standing panic disorder.

The Two Most Important Classifications in Psychiatry

The International Classification of Diseases (ICD), developed by WHO
The Diagnostic and Statistical Manual of Mental Disorders (DSM), developed by the American Psychiatric Association in collaboration with other groups of mental health professionals

The International Classification of Diseases (ICD), Chapter V

Produced by WHO as an aid to the collection of international statistics about disease
Present edition (ICD-10) was published in 1992 (ICD-11 comes into use January 2022)

Main Categories of ICD-10 Chapter V (F)

FOO-F09: Organic, including symptomatic, mental disorders
F10-F19: Mental and behavioral disorders due to psychoactive substance use
F20-F29: Schizophrenia, schizotypal, and delusional disorders
F30-F39: Mood (affective) disorders
F40-F49: Neurotic, stress-related, and somatoform disorders
F50-F59: Behavioral syndromes associated with physiological disturbances and physical factors
F60-F69: Disorders of adult personality and behavior
F70-F79: Mental retardation
F80-F89: Disorders of psychological development
F90-F99: Behavioral and emotional disorders with onset usually occurring in childhood or adolescence

The ICD-10 Multi-Axial System of Diagnosis

Views the patient's problem within a broader context, which includes:

Clinical diagnosis,
Assessment of disability, and
Psychosocial factors

In ICD-10, multi-axial diagnoses are made along three axes as follows:

ICD-10 Multi-Axial System Axes

Axis I - Clinical Diagnoses

This includes all disorders, both psychiatric and physical, including learning disability and personality disorders.

Axis II - Disabilities

Conceptualized in line with WHO definitions of impairments, disabilities, and handicaps. It covers a number of specific areas of functioning which are rated on a scale of 0 (no disability) to 5 (gross disability):

Personal Care: Personal hygiene, dressing, feeding, etc.
Occupation: Expected functioning in paid activities, studying, homemaking, etc.
Family and Household: Participation in family life.
Functioning in a Broader Social Context: Participation in the wider community, including contact with friends, leisure, and other social activities.

Axis III - Contextual Factors

The factors considered to contribute to the occurrence, presentation, course, outcome, or treatment of the present Axis I disorder(s). They include problems related to:

Negative events in childhood
Education and literacy
Primary support group, including family circumstances
Social environment
Housing or economic circumstances
(Un)employment
Physical environment
Certain psychosocial circumstances
Legal circumstances
Family history of disease or disabilities
Lifestyle or life-management difficulties

The Diagnostic and Statistical Manual (DSM)

A document of the American Psychiatric Association (APA)

DSM-V, the latest edition, was published in May 2013.

DSM IV, published in 1994, is still in use.
DSM-IV Textual Revision (DSM-IV-TR), published in 2000; contains a small number of textual changes and updates the classification as an educational tool, but contains no significant alterations to the diagnostic criteria.

DSM-IV retains the multi-axial nature of DSM-III.

The Five Axes of DSM-III and IV:

Axis I - Clinical Syndrome or Psychiatric Diagnosis
Axis II - Personality Disorders
Axis III - Physical Disorders and Conditions
Axis IV - Psychosocial Stressors
Axis V - Highest Level of Adaptive Functioning in the Last Year (Global Assessment of Functioning - GAF)

Objections to Classification or Disadvantages of Classification

People feel you are labeling patients by classifying them. Psychiatric disorders are not conditions readily accepted in society.
Most of the diagnoses in psychiatry don't fall into neat categories.

Importance or Advantages of Classification

Helps to distinguish one psychiatric diagnosis from another.
Clinicians can offer more effective treatment.
For scientific communication (common language among health professionals).
Prediction of prognosis.

Practice Questions

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