Chapter 3.2: Diagnosing Psychological Disorders

Diagnosing Psychological Disorders: Foundations in Classification

Diagnostic classification

• Classification is central to all sciences

• Assignment to categories based on shared attributes or relations

Why is classification important in science and human behavior?

Classification allows for effective communication, organization of knowledge, and advances in understanding by categorizing and labeling objects or experiences.

A clinician can form general conclusions and establish a prognosis, which...

refers to the likely future course of a disorder under certain conditions.

What is an idiographic strategy to diagnosis?

An approach that focuses on understanding an individual's unique personality, cultural background, or situational factors.

How is the idiographic strategy useful in making a diagnosis/treatment plan?

The information lets clinicians tailor their treatment to the person.

What is a Nomothetic strategy?

The attempt to name or classify a specific psychological disorder, to make a diagnosis.

examination of large groups of people with the same disorder to note similarities and develop general laws

How does the Nomothetic Strategy contribute to making a diagnosis?

When we identify a specific psychological disorder, such as a mood disorder, in the clinical setting, we are making a diagnosis.

Terminology of Classification:

Classification: Broad grouping or categorizing based on shared characteristics.

Taxonomy: Classification in a scientific context. (if the subject is psychology—behaviors)

Nosology: Scientific Classification of psychological or medical phenomena.

Nomenclature: Names or labels of disorders within a nosological system.

What classification systems are commonly used in North America for diagnosing psychological disorders?

The DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) and the ICD-10 (International Classification of Diseases, 10th Edition).

The Diagnostic and Statistical Manual of Mental Disorders (DSM):

• Updated every 10 to 20 years
• Current edition (released May 2013): DSM-5
• Previous edition called DSM-IV-TR

The ICD-10 (International Classification of Diseases).

• International Classification of Diseases (ICD-10)
• Published by the World Health Organization (WHO)

What recent developments have affected the classification of psychopathology?

Significant changes in classification approaches, question of reliability and validity in diagnosis with ongoing revisions in systems like the DSM-5.

What are some controversies surrounding the classification of human behavior?

Controversies include the definitions of "normal" and "abnormal," the appropriateness of creating categories like mania and depression, and whether behavior should be viewed on a continuum rather than in distinct categories.

What are the two main approaches to classifying psychological disorders?

The categorical approach (distinct categories) and the dimensional approach (quantifying attributes on a scale).

What is the classical (or pure) categorical approach to classification?

strict categories (e.g., you either have social anxiety disorder or you don't)

It assumes each disorder has a clear underlying cause and requires meeting specific criteria for diagnosis, with each disorder being fundamentally different from others.

What is the dimensional approach to classification?

classification along dimensions (e.g., different people have varying amounts of anxiety in social situations)

It involves quantifying various attributes of a disorder on a scale, creating a profile of emotional functioning rather than fitting into distinct categories.

What is the prototypical approach to classification?

combines classical and dimensional views

It combines categorical and dimensional elements by identifying essential characteristics of a disorder while allowing for nonessential variations.

What are key issues related to reliability in classification systems?

Reliability refers to the consistency of diagnoses across different clinicians and time periods. Unreliable systems can lead to biases and inconsistent diagnoses.

What are some challenges with diagnosing personality disorders?

Diagnoses of personality disorders can be inconsistent due to biases and variability among clinicians, indicating a need for more reliable criteria.

What are the types of validity important for a diagnostic system?

Construct Validity: Criteria should accurately identify and distinguish between different disorders.

Predictive Validity: The diagnosis should predict the likely course of the disorder and treatment outcomes.

Content Validity: The criteria should reflect the way experts in the field understand the disorder.

What was the state of psychopathology diagnosis/classification before 1980?

diagnoses were made based on biological or psychoanalytic theory. Classification was diverse and inconsistent, with many systems in use worldwide, leading to confusion and varying interpretations of disorders.

How did the introduction of DSM-III in 1980 revolutionize classification?

• Classification newly relied on specific lists of symptoms, improving reliability and validity

• Diagnoses classified along five "Axes" describing types of problems (e.g. disorder categories, health problems, life stressors)

DSM-4 was introduced in 1994. What are its notable changes?

• Eliminated previous distinction between psychological vs. organic mental disorders
• Reflected appreciation that all disorders are influenced by both psychological and biological factors
• DSM-IV-TR ("text revision" of DSM-IV) incorporated new research and slightly altered criteria accordingly

How did the DSM-5 change from the DSM-4?

• Removed axial system
• Clear inclusion and exclusion criteria for disorders
• Disorders are categorized under broad headings
• Empirically-grounded, prototypic approach to classification

Emperical

based on observation or experiment and not on theory

How is adding a new disorder approached?

• New disorder labels are created when groups of individuals are identified whose symptoms are not adequately explained by existing labels.

An example of a new disorder added in the DSM-5 is Premenstrual dysphoric disorder. It is relatively rare and symptoms include severe emotional disturbance present during the majority of premenstrual phases

An example of new disorder that did not make it into the DSM-5: Mixed anxiety-depression. There was insufficient research to justify the creation.

Unresolved Issues in DSM-5 include...

Comorbidity:

• Defined as two or more disorders for the same person

• High comorbidity is extremely common

• Emphasizes reliability, maybe at the expense of validity (i.e., may artificially “split” diagnoses that are very similar)

Dimensional classification:

• DSM-5 was intended to move toward a more dimensional approach, but critics say it does not improve much from DSM-IV.

Labeling issues and stigmatization:

• Some labels have negative connotations and may make patients less likely to seek treatment